Depending on the counting convention used, and including all titles, charts, and edited collections, there may be currently over 500 books in Isaac Asimov's bibliography— as well as his individual short stories, individual essays, and criticism. For his 100th, 200th, and 300th books (based on his personal count), Asimov published Opus 100 (1969), Opus 200 (1979), and Opus 300 (1984), celebrating his writing. According to UNESCO's Index Translationum database, Asimov is the world's 24th most-translated author.