Isaac Asimov was a Russian-born American author and professor of biochemistry, best known for his works of science fiction and for his popular science books. He is considered one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90, 000 letters and postcards. Asimov is widely known for his Foundation series, which chronicles the fall of the Galactic Empire and the establishment of a new foundation of knowledge and culture. Asimov's Foundation series is considered one of the most influential works of science fiction ever written.