Isaac Asimov (1920-1992) was one of the most prolific American writers of the 20th century. During his lifetime he published 40 novels, 383 short stories, and over 280 non-fiction books. His most famous and influential works were the Robot series, the Foundation series, and the Galactic Empire series. These began as individual short stories which were then compiled into novels and later expanded on, connecting to each other as the 'Foundation universe'.

Robot series: 37 short stories, 4 novels, plus 'I, Robot' which is listed as a novel and a collection because of the additional frame story which is not reprinted in short story collections. 'The Complete Robot' is 31 of the 37 stories. 'The Rest of the Robots' contains 8 short stories and 2 novels, but some paperback editions exclude the two novels, sometimes titled 'Eight Stories from the Rest of the Robots'. Several other authors have written novels in the Robot series since Asimov's death.

The First three Foundation novels were collected from short stories, and the later Foundation titles were written as novels. After Asimov's death, a second prequel trilogy was written by other authors; Foundation's Fear (1997) by Gregory Benford, Foundation and Chaos (1998) by Greg Bear, and Foundation's Triumph (1999) by David Brin.