Opus 100 is a collection by American writer and scientist Isaac Asimov. It was published by Houghton Mifflin on 16 October 1969. Asimov chose to celebrate the publication of his hundredth book by writing about his previous 99 books, including excerpts from short stories and novels, as well as nonfiction articles and books. Opus 100 also includes five complete science fiction stories and one complete science essay. Source: Wikipedia (en)