Sagan advocated scientific skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence ( SETI). His papers, containing 595,000 items, are archived at The Library of Congress. He also wrote the 1985 science fiction novel Contact, the basis for a 1997 film of the same name. The book Cosmos was published to accompany the series. The most widely watched series in the history of American public television, Cosmos has been seen by at least 500 million people in 60 countries.

He wrote many popular science books, such as The Dragons of Eden, Broca's Brain, Pale Blue Dot and narrated and co-wrote the award-winning 1980 television series Cosmos: A Personal Voyage. Sagan published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books. Initially an assistant professor at Harvard, Sagan later moved to Cornell where he would spend the majority of his career. Sagan argued the hypothesis, accepted since, that the high surface temperatures of Venus can be attributed to, and calculated using, the greenhouse effect. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.

Carl Edward Sagan ( / ˈ s eɪ ɡ ən/ SAY-gən November 9, 1934 – December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator.

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