WHAT ARE THESE GRACEFUL VISITORS TO OUR SKIES? WE NOW KNOW THAT THEY BRING BOTH LIFE AND DEATH AND TEACH US ABOUT OUR ORIGINS. Comet begins with a breathtaking journey through space astride a comet. Pulitzer Prize-winning astronomer Carl Sagan, author of Cosmos and Contact, and writer Ann Druyan explore the origin, nature, and future of comets, and the exotic myths and portents attached to them. The authors show how comets have spurred some of the great discoveries in the history of science and raise intriguing questions about these brilliant visitors from the interstellar dark. Were the fates of the dinosaurs and the origins of humans tied to the wanderings of a comet? Are comets the building blocks from which worlds are formed? Lavishly illustrated with photographs and specially commissioned full-color paintings, Comet is an enthralling adventure, indispensable for anyone who has ever gazed up at the heavens and wondered why. "SIMPLY THE BEST." *The Times of London "FASCINATING, EVOCATIVE, INSPIRING." *The Washington Post "COMET HUMANIZES SCIENCE. A BEAUTIFUL, INTERESTING BOOK." *United Press International "MASTERFUL . . . SCIENCE, POETRY, AND IMAGINATION." *The Atlanta Journal & Constitution

Although Galileo Galilei lived and died centuries ago, his story is more relevant to our lives than we might realize. Today we face enormous challenges such as climate change that are disregarded or questioned by those who fear that their implications will damage business profitability. Others posit a false dichotomy between religion and science in order to reject scientific evidence whose implications they fear. Galileo confronted this problem 400 years ago. His discoveries were based on observation and experiment. His telescopes revealed previously unknown planets, moons orbiting other planets, and other discoveries that essentially confirmed the Copernican universe that the Church had rejected as heretical because Church theologians insisted on a literal reading of the Bible. Even St. Augustine in the fifth century maintained that the Bible pertained to the realm of faith, not reason. But when Galileo argued essentially the same position before an ecclesiastical court in Rome, he was forbidden from publishing any more books. Livio's life of Galileo shows us how the great thinker made his discoveries about the heavens and also formulated fundamental laws of physics. As an astrophysicist, Livio brings insight into how Galileo reasoned his way to his conclusions, which we know today were accurate. Along with Newton, Galileo remains one of the two great figures at the dawn of the scientific revolution. He insisted on reaching the widest audience possible, publishing his work in Italian rather than Latin as had been the case until his time, when vernacular languages were rapidly replacing Latin throughout Europe. Galileo believed that every educated person should know science as well as literature. Did Galileo actually say at the end of his trial when he was forced to recant his discoveries, as legend has it, And still it moves, referring to the motion of the earth around the sun? Not likely, says Livio, but Galileo nonetheless remains an inspiration to scientists and those who value open-minded inquiry, which as Livio reminds us, remains threatened even today.

More of Isaac Asimov's weekly science columns for the Los Angeles Times and those his wife, Janet, wrote during his illness and after his death in April 1992. The Asimovs discuss how close we are to producing life in a lab, the latest revelations about dinosaur extinction, recent startling sightings of planets and stars, if we can establish colonies on Mars, if computer intelligence can ever surpass human intelligence, and the gravest dangers to our environment. Annotation copyright by Book News, Inc., Portland, OR

Frontiers probes the furthest boundaries of prehistory, science, earth space and the universe. It is a collection of short, topical and intriguing essays through which Isaac Asimov, the incomparable writer of science fiction, proposes brand new answers to classic scientific conundrums.

During the sixteenth and seventeenth centuries a radical change occurred in the patterns and framework of European thought. In the wake of Copernican theory and discoveries through the telescope, the notion of an ordered cosmos of "fixed stars" gave way to that of a universe infinite in both time and space-with significant and far-reaching consequences for human thought. Alexandre Koyré brilliantly interprets this revolution in terms of the change that occurred in our conception of the universe and our place in it, and illustrates the primacy of this change in the development of the modern world. "An important contribution to the problem of the transition from the world view characteristic of the medieval centuries to that which rapidly gained acceptance after the seventeenth century." (Philosophical Quarterly) "Koyré has provided the material and has illuminated it with uniformly perceptive and occasionally brilliant commentary.... An important contribution to the study of 17th-century thought." (Thomas S. Kuhn, Science) "A model of scholarliness without pedantry, of clarity without oversimplification." (Arthur Koestler, Encounter) "Surely a work that will be welcomed alike by the scientist, philosopher, and historian of ideas." (Philosophy and Phenomenological Research) Alexandre Koyré was a member of the Institute for Advanced Study, Princeton, and professor at the Ecole Pratique des Hautes Etudes in Paris. His books include Discovering Plato and Newtonian Studies.