Astronomer, planetary scientist, astrophysicist, exobiologist, educator, public figure, skeptic-all these hats represent important parts of Carl Sagan's complex, multifaceted career. Perhaps best known as the host of the popular television series Cosmos, Sagan offered to the world his extraordinary gift for cross-disciplinary research, his deep well of integrated visions and fruitful ideas, his vivid imagination, and his wealth of nonstop enthusiasm. This concise, lively biography examines Carl Sagan's steady growth as a man, as a scientist, and as a communicator-a man who had both odd quirks and great charisma, who had an immensely eclectic knowledge base and a unique understanding of the central place of science in the human experience, all of which dovetailed smoothly with his phenomenal ability to communicate. Separate chapters are devoted to Sagan's interest in the origin of life, the search for extraterrestrial intelligence (SETI), and his work on Cosmos, where he collaborated with Ann Druyan, whom he eventually married and who remained his wife to the end of his life. There are also sections on Sagan's public advocacy for science and critical stance toward pseudoscience and his role as an activist for the environment and the safe use of atomic power. This updated, paperback edition of Carl Sagan: A Biography contains many new photos as well as textual additions by Ann Druyan. Veteran science writers Spangenburg and Moser have captured much of the enthusiasm, gift for effective communication, and unflinching honesty that characterized Carl Sagan's life and career.