Carl Sagan was an American astronomer, astrophysicist, cosmologist, author, and science communicator. He is best known for his work as a science popularizer and communicator, and he was also a highly regarded astronomer and astrobiologist. Sagan was a professor of astronomy and space sciences at Cornell University, and he was the director of the Laboratory for Planetary Studies. He wrote more than 600 scientific papers and popular articles, and he was the author of several books, including the Pulitzer Prize-winning book, "The Dragons of Eden". Sagan was a passionate advocate for science and exploration, and he was a major contributor to the public understanding of science. He was also a strong advocate for nuclear disarmament and environmental protection. Sagan's legacy lives on in the form of the Carl Sagan Institute, which is dedicated to the exploration of the universe and the search for extraterrestrial life.