Carl Edward Sagan was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator.

He is best known for his research on the possibility of extraterrestrial life, including the experimental demonstration of the production of amino acids from basic chemicals by exposure to light. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, which were universal messages that could potentially be understood by any extraterrestrial intelligence.

Initially an assistant professor at Harvard University, Sagan later moved to Cornell University, where he spent most of his career. He was a prolific writer, having published more than 600 scientific papers and articles, and authored, co-authored, or edited over 20 books. Some of his popular science works include The Dragons of Eden, Broca's Brain, Pale Blue Dot, and The Demon-Haunted World.

Sagan co-wrote and narrated the award-winning 1980 television series Cosmos: A Personal Voyage, which became the most widely watched series in the history of American public television. A companion book, also titled Cosmos, was published alongside the series. He also wrote the 1985 science-fiction novel Contact, which inspired the 1997 film of the same name.

He was a public advocate for skeptical scientific inquiry and the scientific method, pioneering the field of exobiology and promoting the search for extraterrestrial intelligent life through SETI. Over his career, Sagan received numerous awards and honors, including the NASA Distinguished Public Service Medal and the National Academy of Sciences Public Welfare Medal, among others.

Carl Sagan married three times and had five children. He passed away after developing myelodysplasia, dying of pneumonia at the age of 62 on December 20, 1996.