Isaac Asimov (born Isaak Ozimov; c. January 2, 1920 – April 6, 1992) was an American writer and professor of biochemistry at Boston University. He was known for his works of science fiction and popular science. Asimov was a prolific writer, and wrote or edited more than 500 books and an estimated 90,000 letters and postcards. His books have been published in 9 of the 10 major categories of the Dewey Decimal Classification.
Asimov wrote hard science fiction and, along with Robert A. Heinlein and Arthur C. Clarke, he was considered one of the "Big Three" science fiction writers during his lifetime. Asimov's most famous work is the Foundation Series; his other major series are the Galactic Empire series and the Robot series. He wrote hundreds of short stories, including the social science fiction "Nightfall", which in 1964 was voted by the Science Fiction Writers of America the best short science fiction story of all time.