Carl Edward Sagan (1934 - 1996) was an American astronomer and science popularizer. He pioneered exobiology and promoted the Search for ExtraTerrestrial Intelligence (SETI). He is world-famous for his popular science books and the television series Cosmos, which he co-wrote and presented. In his works he frequently advocated the scientific method. From Cosmos and his frequent appearances on The Tonight Show, Sagan became associated with the catch phrase "billions and billions." Carl Sagan also wrote an introduction for the best selling book by Stephen Hawking, A Brief History of Time. The landing site of the unmanned Mars Pathfinder spacecraft was renamed the Carl Sagan Memorial Station in honor of Dr. Sagan on July 5, 1997. Asteroid 2709 Sagan is also named in his honor.