Carl Edward Sagan (November 9 1934 ? December 20 1996) was an American astronomer and astrochemist and a highly successful popularizer of astronomy, astrophysics, and other natural sciences. He pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence . He is world-famous for writing popular science books and for co-writing and presenting the award-winning 1980 television series A Personal Voyage, which has been seen by more than 600 million people in over 60 countries, making it the most widely watched PBS program in history. A book to accompany the program was also published. He also wrote the novel Contact, the basis for the 1997 Robert Zemeckis film of the same name starring Jodie Foster. During his lifetime, Sagan published more than 600 scientific papers and popular articles and was author, co-author, or editor of more than 20 books. In his works, he frequently advocated skeptical inquiry, humanism, a