A New York Times Notable Book of the Year

A New Scientist Bestseller


Good Reviews: 26

Bad Reviews: 0

Read an Excerpt from PLANET QUEST!

Description--PLANET QUEST

A new era in the exploration of the universe has begun. After decades of intense scientific investigation, planet hunters have discovered the first alien solar system around a star like our own Sun. Since then, armed with new insight and technology, astronomers have been discovering planets at an exhilarating pace. Every day seems to bring us closer to finding an Earthlike planet, perhaps harboring life, and the resolution of the grandest human mystery of all: Are we alone?

Now astronomer and internationally acclaimed author Ken Croswell has written the definitive guide to the culmination of the scientific revolution that began with Copernicus. Weaving together the personal travails of the scientists who made the key discoveries, Dr. Croswell marshals extensive research and interviews to bring to life this epic of scientific adventure--in language so clear that anyone can understand. He succinctly defines the essential features of our own solar system, then recounts the stories of the discovery of Uranus, Neptune, and Pluto and the search for the mysterious Planet X. From there we leap with him beyond our solar system's edge, following the pioneers of science in their quest for planets around other stars.

In the decades preceding ours, disappointment and frustration reigned among astronomers, as claims of discovery based on necessarily infinitesimal measurements were made only to be disproved and cast back into the void of obscurity. But planets recently found orbiting a dead star known as a pulsar heralded the new era of planetary exploration that Planet Quest opens the door on with the discovery of a Jupiter-sized planet circling 51 Pegasi, a star virtually identical to the Sun. The discovery of this planet was quickly followed by another, found quietly wending its way around the star 47 Ursae Majoris.

For the first time, as Dr. Croswell lucidly explains, we have demonstrated that the universe at large does in fact possess the four basic astronomical ingredients for life. Moreover, he shows how new space-based and technologically advanced observatories could provide direct detailed images of our new neighbors. Perhaps someone, or something, will be waving back.

"An exciting story well told. Croswell has gone whenever possible directly to the scientists involved to present an interesting and comprehensive history of the search for planets both inside and outside our solar system."
--Lawrence Krauss, Case Western Reserve University; author of The Physics of Star Trek

"What a great read! Ken Croswell writes compellingly about the hunt for extrasolar planets, how they have been found, and the prospects for future planet discoveries. He captures the loneliness of the planet hunter, the agony of defeat, the pain of the retracted publication, and the thrill of the find. When our descendants look back on this age, they will mark this time as one of profound change in the history of astronomy."
--Richard N. Zare, Stanford University

"The implications of the monumental discovery of other planets orbiting distant stars require us to examine anew our conception of the universe--for where there are planets, there can be life. Ken Croswell takes the reader on this voyage to a new world view. Reading this book is like sailing with Columbus."
--Peter D. Ward, University of Washington, coauthor of Rare Earth

"A thrilling account of the discovery of planets in the solar system and elsewhere that stands out for its human interest and its accuracy."
--Sir John Maddox, editor emeritus, Nature

Good Reviews--PLANET QUEST

Publishers Weekly:

In a book as rich in story as it is in science, Croswell takes readers on an epic journey through time and space. The story opens in Rome on February 17, 1600, where defrocked priest Giordano Bruno is being led to his execution; it ends on the threshold of interstellar exploration. To Bruno, who lost his life for proclaiming an infinite universe filled with stars and planets beyond imagining, science was not the enemy of religion but the tool of revelation of God's infinite splendor. To Croswell, the actions of Bruno's accusers demonstrated what they most feared: the insignificance of their own lives. This book--filled with stories of disappointment and triumph, of missed opportunity and unexpected discovery--recounts four centuries of interwining quests for grand ideas and individual glory by scientists and philosophers struggling to make sense of our place in the cosmos. It tells of three contentious solar planets "discovered" at various times: one (Vulcan, inside Mercury's orbit) was proven not to exist; one (Planet X, beyond Neptune and Pluto) was once avidly sought but now seems chimerical; and one (Pluto) may simply be part of a "cometary belt" beyond Neptune. Tales of scientific competition and heroic admissions of error mark the quest to become the 20th-century Columbus, the discoverer of the first extra-solar world. Soon the number of known planets beyond the solar system will far exceed the nine in our small neighborhood. We are poised, Croswell shows in his exceptional book, on an era of planet quest that promises to propagate the best and worst of humanity to other stars and worlds.

Scientific American:

Astronomers [have] discovered the first planets circling Sunlike stars, proving that our solar system is not unique. This book offers a fine introduction to this mind-opening discovery. Ken Croswell takes a charming, historical approach, beginning with Giordano Bruno's vision of a multitude of worlds and continuing through the personalities and techniques involved in the latest findings.

The New York Times Book Review:

It is often said that interest in science is stimulated by its many practical applications. Nothing could be further from the truth. In general, we are happy to take for granted the practical applications of science in everyday life (when was the last time you paid silent homage to Michael Faraday as you turned on an electric light?); what fascinates us is the power of science to address the really big questions, most of which are of absolutely no practical consequence whatever--questions, as the novelist Douglas Adams once memorably phrased it, about "Life, the Universe and Everything." This is why books about cosmology, evolutionary biology, and consciousness sell better than books about chemistry, ecology, and thermodynamics. It is not that we doubt the practical importance of catalysis, the carbon cycle, and combustion; it is just that we find these things less gripping than the big bang, the death of the dinosaurs, and the search for a coherent theory of mind.

Planet Quest by Ken Croswell falls squarely into the useless-but-fascinating school of popular science writing. It is an excellent introduction to a branch of astronomy that may eventually help to establish the presence or absence of life elsewhere in the universe. Over the centuries, since astronomers first established that the Earth is but one among a number of planets orbiting the Sun, the question of whether other planets may support life has been the subject of much speculation....

Croswell recounts well the early frustrations of extrasolar planetary astronomy, as first one and then another reported planetary sighting turned out to be false. The field has only really come into its own in the 1990s. Surprisingly, the first good evidence for an extrasolar planet came from studies of pulsars, rapidly spinning neutron stars very unlike our Sun; not until 1995 did two Swiss astronomers detect the first hard evidence of an extrasolar planet orbiting a Sunlike star. Since then, improved measurement techniques have led to a rush of discoveries. As Croswell says, "a new era in the exploration of the universe has commenced." Over the next few years, we can expect the head count of extrasolar planets to grow to the point where we can begin to judge just how normal or abnormal is our own solar system, and just how common or uncommon in the universe are planetary systems capable of supporting life. Amazingly, astronomy may even provide us with information about planetary atmospheres that offers indirect clues to the presence or absence of life itself.

Astronomy has always attracted more than its fair share of publicity because of the large questions that it promises to help answer. Commenting on his mail, one astronomer tells Croswell: "The public wants to know. You have found some things: so what? And the `so what' is quite profound. Is our Earth unique? Are there other earths out there? Did Jesus have to go to all of those planets?" Croswell is an excellent guide to how far astronomy has come in answer to these latter questions (the respective answers, by the way, are: "probably not," "probably, but we don't know how many," and "that's not a proper question for an astronomer.") He gives us a feel for the excitement of the quest without falling into the trap of sensationalism.

Planet Quest is of no practical use whatever. It won't help you change a light bulb, but it is fascinating and worthwhile nonetheless.
--John Durant

Sky and Telescope:

Ever since humans have known that the stars are truly objects like our Sun, we have wondered if those distant suns possessed systems of planets like ours. Indeed, this has been one of the prime questions of astronomy. It teases our curiosity like none other, and of all the astronomical quests, is most relevant to all human beings. It bears mightily on the supreme burning question: what are the significance, place, and future of humans in this universe? But importance is not enough to produce a scientific discovery. In science, for sure, wishing does not make it so. Generation after generation of astronomers have had to shrug and walk away from the challenge of finding other solar systems. Extrasolar planets are very hard to find.

Finally, after hundreds of years of disappointment, false "discoveries," and undue optimism, the search has succeeded--in a big way....Croswell's book is a treasure-trove of information about ideas and activities going back to the year 1600, when Giordano Bruno was burned at the stake in the Campo di Fiori ("The Field of Flowers," now a large parking lot) in Rome for proposing that there was an infinity of worlds in the universe. Croswell presents a steady stream of remarkable historical events. I always wonder how authors gather such collections of odd and fascinating facts--indeed, where do they find the time! It is hard to put the book down in these sections.
--Frank Drake


Croswell digs deep into the controversies and personalities surrounding the discovery of extrasolar planets. His book contains quotes from the researchers, and after reading the book, you feel as if you know who they are. You witness the drama of discovery unfolding, and you empathize with the hopes and frustrations of the astronomers. Planet Quest is strewn with fascinating tidbits including, for instance, that a Canadian planet-hunting team used the deadly poisonous gas hydrogen fluoride in its spectrograph....

Croswell weaves the facts together into a story. By delving into the history, which is rife with false alarms and stumbling, bumbling, and fumbling, Croswell does a magnificent job of providing a broad perspective of the entire subject.
--Robert Naeye

The Cleveland Plain Dealer:

Planet Quest is everything a good science-for-the-public book should be. The book's subject is clear and its significance easy to understand. The writing is lucid and the explanations of scientific principles and methods are coherent. The information in the book is up to date; there are lots of clear illustrations, and the book has a bibliography and a glossary of scientific terms. Best of all, Croswell never forgets why his readers will be interested in the story he has to tell.
--John R. Alden


Ken Croswell has everything needed in a great science writer. He knows his subject and understands the joys, difficulties, and frustrations of being an astronomer. He has great skill in interviewing the scientific protagonists and drawing from them the details of the excitement and disappointments of their endeavours; many of these interviews are quoted verbatim. And he can tell a superb story, which is compelling and complete. I particularly liked his discussion of the way the media reacted to the "new planet" news. The book is riveting. And what is more, it has an extensive note and reference section.
--David W. Hughes

Space Views:

Ken Croswell's Planet Quest takes the reader on a tour of the history of planet discoveries, from the discovery of the outer planets in our own solar system through the alleged discoveries of planets around Barnard's Star and other stars, which were later refuted, to the confirmed discoveries of pulsar planets and the wealth of new extrasolar planets found in recent years.

Croswell explains the science and the observational techniques at a level easily understood by the layman. Moreover, his interviews with dozens of scientists involved in the search adds an extra, human dimension to the subject, as we find out about the ups and downs, the cooperation and the conflicts, researchers in the field have encountered. The book includes a detailed glossary of terms and names used in the book, along with a bibliography that includes general works and scientific papers, that make the book a good reference work in addition to its strengths as a tale of discovery....

For those looking to learn more about the search for extrasolar planets, it will be hard to beat Planet Quest.

Astronomy Now:

Planet Quest is a clear, straightforward, and easy-to-read account of the history of the search for planets, the recent discoveries and the techniques which have made them possible, and the future directions in which the search is heading. It also includes a concise discussion of wider issues relating to life, communication, and interstellar travel. The text is complemented by useful notes and a substantial bibliography.

The book highlights the work and views of many of the key individual researchers, their successes and failures, disputes and conflicts, thereby bringing to life the reality of scientific endeavour. Ken Croswell has succeeded admirably in putting interesting science into a framework which combines a scientific detective story with an adventure of exploration.

Because no previous knowledge of astronomy is assumed, and the relevant background (including a useful glossary) is provided, the book is accessible to a wide general readership....

For those who wish to gain a clear understanding of the nature and significance of the quest coupled with a lucid review of the results so far, Planet Quest will be hard to beat.
--Iain Nicolson


"Ksiazka powstala na podstawie rozmow m. in. z Bohdanem Paczynskim i Aleksandrem Wolszczanem"--jak informuje na okladce wydawca, wedlug Przedmowy do wydania polskiego autora. Jednak tlumacz nie popisal sie oryginalnoscia, przekladajac tytul oryginalu Planet Quest jako Lowcy planet...Pozycje te (w wydaniu polskim) roznia sie na szczescie nie tylko podtytulami, ale rowniez prezentowanym poziomem wiedzy--na korzysc oczywiscie Kena Croswella (autora, dodajmy, rowniez znakomitej ksiazki pt. Alchemia nieba).
--T. Zbigniew Dworak

Kirkus Reviews:

A lively, timely history of the search for extrasolar planets--today's hottest astronomical game....Croswell provides engaging portraits of the astronomers (from Giordano Bruno through Geoffrey Marcy, one of those who confirmed 51 Pegasi's planet) as well as a clear, lively summary of the scientific material. A thoroughly readable addition to the astronomy bookshelf.

New Scientist:

Few areas of research have attracted as much public and media interest as that covered by Ken Croswell in Planet Quest--the long and sometimes tortuous path that has finally led to the discovery of planets orbiting other suns. Our fascination with this find is, of course, down to the widespread belief that planets and their satellites are the most likely setting for the evolution of life. This is an integral part of the story that Croswell skilfully unfolds.

We are first given a thorough grounding in the science of our solar system, and reminded how its outer planets were discovered. The abortive searches for Vulcan, which was believed to be closer to the Sun than Mercury, and Planet X, thought by some to exist beyond the orbit of Pluto, are included to help make us aware of the pitfalls that can occur along the way. We learn how the giant Jupiter protects the inner planets of our solar system from the vast majority of cometary impacts, and so may allow periods of calm long enough for life to evolve.

The heart of this book is naturally about the first discoveries of planets around distant stars. Croswell presents this fascinating story very well. He often quotes those directly involved in the search, allowing us to share their feelings as hopes were dashed or tentative discoveries confirmed....

These techniques are not sensitive enough to reveal Earthlike planets, but Croswell consoles us by describing how techniques such as adaptive optics and infrared interferometry may be able to do so in the future. It is even possible that, by spectral analysis of their atmospheres, we might detect the presence of ozone, an excellent marker for the presence of oxygen, which could indicate a life-bearing planet.

Croswell ends this excellent book with a 50-page section containing a glossary of scientific terms used, and notes linked to each chapter. These give references stretching as far back as 1838. This section is just one indication of the detailed research Croswell has put into his book, making it a joy for any student of the subject. I find it hard to see how anyone could have done a better job in bringing this exciting field to the general reader.
--Ian Morison

The Irish Astronomical Journal:

Following Croswell's highly successful The Alchemy of the Heavens, this new book on humankind's search for planets other than our own is most welcome. Again, the style is journalistic, clear, and very easy and enjoyable to read. The subject, a quest for planets, has been around a long time. In 1600, Giordano Bruno met the same fate as Galileo when he wrote his treatise, On the Infinite Universe and Worlds! Croswell takes the reader through the whole story of this quest, through to modern times, Planet X, the Vega effect, Jupiter-like objects, pulsar planets, and to what may become one day, a harvest of planets....Planet Quest will, undoubtedly, appeal to everyone.


As the headlines tell of the discovery of yet another planetary system, it is sometimes difficult to remember the long struggles that enabled astronomers to finally achieve success. Croswell's timely book brings us the history of that search, beginning with the speculations of Copernican times and ending with the application of such powerful modern techniques as radio pulse timing, optical precision position measurement, and Doppler velocity changes. In between are several chapters with an excellent description of our own solar system. The book is well planned and generally well written, although occasionally repetitious, perhaps in an attempt to make each chapter self-contained. The treatment of the technical issues, a combination of thoughtful prose and useful diagrams, is especially good. The thorough nature of the presentation coupled with the imaginative use of quotations from scientists involved in the story ensures that the book will not quickly be outdated, even though more planetary systems will surely be found. Extensive glossary; chapter notes and references. Recommended as both a comprehensive introduction to the subject and a source of information about the solar system and neighboring stars.
--D. E. Hogg


By now the story of the discovery of planets around far-off stars is probably familiar to all astronomy buffs who haven't been dozing at their telescopes. But Ken Croswell adds details to the outline and flesh to the skeletal personalities reported on in the press. Central to the book is the hubbub surrounding the discovery of the planet orbiting the star 51 Pegasi, including accounts of how the British journal Nature muzzled its discoverers and of the Nightline interview during which a second (subsequently retracted) planet was announced. Croswell, a Berkeley-based astronomer, also tells the story of previous generations of planet hunters who looked for the tiniest wiggles in the nearby stars.

The Observatory:

Croswell spends the first quarter of the book on the solar system and by halfway we reach the discovery of the pulsar planets. He mentions the fascinating idea due to George Wetherill that life in our solar system developed partly because the gravitational influences of Jupiter and Saturn protected the inner planets by deflecting many large fragments from the outer solar system on their way towards the Sun. The remainder of the book describes the discovery of the planets around normal stars and the plans for extending the search to Earth-mass objects. Finally there is a useful glossary and a 20-page bibliography....

The main strength is Croswell's skill as a populariser of astronomy. He manages to put together the whole subject in a smoothly flowing narrative that relies as much on the personalities involved as on the science.
--Robert Argyle

Star Date:

Ken Croswell has followed up his successful The Alchemy of the Heavens with a new book about astronomy's holy grail, the search for planets around other stars. Planet Quest chronicles the tedious research undertaken over the last half century to produce a flurry of discoveries in just the last three years. Croswell also puts the discoveries in perspective with discussions of how the new planets compare to planets in our solar system and how their parent stars match up to the Sun and other stars in the Milky Way.


Croswell, following his story of the Milky Way (The Alchemy of the Heavens), addresses a most popular topic in astronomy, the planets beyond Pluto....The graphics depict the behavior of neighboring stars from which astrometrists (astronomers who specialize in distance measurements) would infer the presence of planets; indeed, proving a detection is so difficult that there were several false claims before the first confirmed extrasolar planet was announced in 1993. In this history, Croswell interweaves search strategies and techniques with quotations from the scientists involved. The next frontier, finding an Earthlike planet, induces him to muse on the requirements of interstellar travel, a futuristic prospect that concludes this informative explanation of why contemporary astronomy is so exciting.
--Gilbert Taylor

Ad Astra:

Interstellar travel is a rich topic of its own. But consider what one astronomer has to say about the possibilities. In his absorbing book Planet Quest: The Epic Discovery of Alien Solar Systems, Ken Croswell devotes his final chapter ("Into the Cosmos") to our prospects of visiting the extrasolar worlds now emerging in our telescopes.

Croswell soberly discussses the daunting distances, the current impossibility of matter-antimatter and laser drives, and the purely speculative nature of wormhole tunneling and faster-than-light travel. He notes that a realistic first step may be the proposed TAU robotic mission, so named because it would conduct science a thousand astronomical units from the Sun, taking about a century to get there. But in his conclusion he also notes the following: "Yet it would be folly to dismiss the capability of terrestrial civilization a few centuries from now, let alone that of other civilizations which may be millions or billions of years more advanced. Furthermore, if a genuine twin of Earth were discovered around a nearby star, such as Alpha Centauri, Lalande 21185, or Tau Ceti, the urge to explore that world directly would be irresistible."
--George Smith

Physics Today:

The discovery of [extrasolar planets] and the controversy over their nature make a dramatic story, and one well told in Planet Quest by Ken Croswell....The hallmark of Croswell's book is his use of interviews with many of the participants in the discoveries, a technique that makes us feel as if we were present at those discoveries and lays bare the controversies over the differences between brown dwarfs and stars, brown dwarfs and planets, the formation of planets extremely close to their parent star, and the very existence of pulsar planets.
--Steven J. Dick

Scott Shalaway:

For millennia, humankind regarded the Earth as the center of the universe. Only a few hundred years ago did we discover that we are but a small part of a grand universe. Planet Quest by Ken Croswell takes us beyond our own solar system and into the realm of alien solar systems. He reviews the history of astronomy, from Copernicus' discovery that Earth revolves around the Sun to the recent discovery of other solar systems in the universe. This is great science for the masses.

Library Journal:

After summarizing the history of the discovery of outer planets in our solar system, science writer Croswell moves on to the exciting--and apparently authentic--recent discoveries of planets revolving around stars other than our Sun. He tells of a variety of premature "discoveries" that could not be confirmed and of more soundly based findings in the 1990s. He explains well the scientific basis of the search for remote planets and is candid about the rivalries and disagreements in this field. Despite a speculative last chapter on the prospects for interstellar travel, Croswell wisely concentrates in general on the science (not the science fiction) of planetary searching. Highly recommended for both public and academic libraries.
--Jack W. Weigel

University College London:

For background reading on planets around other stars, Planet Quest by Ken Croswell is by far the best of half a dozen or so recent books on the subject.
--Ian Crawford

Journal for the History of Astronomy:

There is a good deal of recent history in this account, well documented with source notes at the end.

Air and Space/Smithsonian:

Ken Croswell's engaging new book, Planet Quest, reviews the fascinating and often erratic journey astronomers have made to finally come to the very recent realization that, yes, there is evidence for other planetary systems--probably.

Croswell tells a candid and vivid story of the search for life on other planets, and then the search for other systems of planets. He lays out the carcasses of present and past careers devoted to the search--and shows how so many of those careers were misled. It all demonstrates that astronomy is a very human and chancy business.

Astronomers today have the tools to measure the excrutiatingly minute periodic shifting of a star in space caused by the gravitational influence of invisible masses of planetary dimensions. But are these masses planets or extremely small stars? How does one distinguish between the two? These types of questions keep Croswell's narrative lively. Thus far, no Earth-type planet has been detected around a solar-type star. What have been found are planets ranging in size from Jovian-scale to hundreds of times larger. This is a good start, and Croswell makes the most of it by arguing that complex life on Earth-type planets requires the existence of Jovian-type planets to act as cosmic brooms sweeping the inner system clear of marauding comets that otherwise would have smashed into the smaller planets, destroying any life struggling to survive on them.

Croswell demonstrates viscerally how delicate the balance of life is here. He shuns questions of how life begins or evolves, dodging the debate over the direction of evolution: Given that life can exist, will it naturally become self-aware and intelligent and venture out into the universe? He does envision a future in which at least one life-form performs this last act: humans. Among those who argue this point, Croswell is one of the most sensitive and effective.
--David DeVorkin

The Wilson Quarterly:

Until a few years ago, only three human beings in history could claim to have discovered a planet, and only one of them--the late Clyde Tombaugh, discoverer of Pluto--lived in the twentieth century. Today, however, a growing number of astronomers can make that claim. We now know of more planets beyond our solar system than within it.

Croswell, an astronomer and the author of The Alchemy of the Heavens, tells the stories behind these and earlier breakthroughs. We learn of the discoveries of Uranus, Neptune, and Pluto, the failed search for a "Planet X" beyond Pluto's orbit, and the quest for planets outside our solar system. The first discovery of an extrasolar planet was made in 1991 by Aleksander Wolszczan [and Dale Frail] in 1991, and was soon followed by a raft of similar breakthroughs by Swiss and American astronomers.

Unfortunately, the history of searches for planets--whether inside or outside our own system--has not always been a happy one. Croswell explains why claims for the discovery of other planets get made in the first place, and how the continued refusal of the data to back up some claims eventually leads to their rejection. He also explains why these searches always involve indirect evidence--usually the distortion of a star's motion by the gravitational pull of its partner--rather than direct observation.

Croswell re-creates one of the shining moments of twentieth-century science. In 1991, English astronomer Andrew Lyne and his team announced the detection of planets around a pulsar (a dead star), which seemed to be the first extrasolar planets. In 1992, however, Lyne found a flaw in his data that invalidated his conclusion. Rather than send a terse letter of retraction to a professional journal, Lyne stood up and explained his error before a gathering of the American Astronomical Society in Atlanta. When he finished, the auditorium of astronomers gave him a standing ovation.

If Croswell's book has a weakness, it is his excessive attention to side issues and even nonissues, including a chapter-long semantic quibble over whether a brown dwarf is or is not a star. As a result, the main story about modern planetary discoveries doesn't begin until page 180.

That said, Croswell's command of the nuts and bolts of the profession enables him to explain what would otherwise be rather esoteric debates. A nice touch is his inclusion of interviews with a number of astronomers involved in the story, together with thumbnail sketches of their careers and accounts of how they came to be astronomers. No parent reading this book can fail to be impressed by these scientists' testimonies to their earliest shaping experiences: "My parents bought me a telescope" or "My father showed me the constellations."
--James Trefil


The fascinating story of the search for planets within and beyond our solar system is the subject of Ken Croswell's book Planet Quest. Although scientific presentations and journal articles give a distilled view of the quest and public presentations are often superficial, the excitement of scientific discovery is preserved in this book.

Speculations on the existence of planets circling other stars can be traced back to Giordano Bruno. It is with Bruno that Croswell begins, and with the very latest discoveries that he ends. The book is remarkably complete and up-to-date. Croswell presents all the major discoveries and all the challenges to the interpretations of the discoveries. More important, he presents all the keys to understanding the difficulties associated with the search for planets. He also covers vital subjects that are not often given adequate attention, such as circumstellar disks, gravitational interactions of protoplanetary bodies, and the discovery of planetary systems around pulsars, rapidly spinning neutron stars that are the remnants of the death of a massive star following a supernova explosion. In addition, Croswell details the "discovery" of planets both within our own system and around other stars that have been discredited or that have vanished as a result of the insidious presence of systematic errors. He describes the evidence, both observational and theoretical, that has convinced astronomers that very low mass objects, some almost certainly planets, have finally been discovered. But these "planets" are a strange lot, with unexpected properties that are proving a challenge to our understanding of the process of planet formation. These discoveries have led scientists to new conclusions about the presence of other Earthlike planets and life elsewhere in the universe and have inspired ambitious plans for future astronomical exploration from the Earth and space to discover Earthlike planets. Croswell presents all this material clearly and perceptively.

Unique to Croswell's approach is his use of personal interviews with key researchers active in the field. Croswell is a trained astronomer who has done his homework; he knows what questions to ask and how to filter and interpret what he hears. His skill as an interviewer and reporter gives us insights we would never get from reading journal papers. We get a taste of the competition among researchers--the egotism of some, the restraint of others--and we see the misunderstandings, the controversies, the arguments over terminology, the excitement of discovery, and the agony of failure. The book is filled with provocative statements that enliven the discussion and that, one suspects, some researchers might not be too pleased to see in print.

Planet Quest documents the history of our attempts to understand our place in the universe. Testifying to our fascination with this subject are the more than twenty pages of bibliographical source material that Croswell has included for those interested in pursuing the details of this remarkable story of discovery.
--Robert P. Stefanik

Read an Excerpt from PLANET QUEST!