Comet begins with a breathtaking journey through space astride a comet. What are these graceful visitors to our skies? We now know that they bring both life and death and teach us about our origins. 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? Comet is an enthralling adventure, indispensable for anyone who has ever gazed up at the heavens and wondered why.