Psychohistorical Crisis is a science fiction novel by American-Canadian writer Donald Kingsbury, published by Tor Books in 2001.

An expansion of his 1995 novella "Historical Crisis", it is a re-imagining of the world of Isaac Asimov's Foundation series, set after the establishment of the Second Empire.

The book is neither officially authorized by Asimov's estate (as they had previously done with the Second Foundation Trilogy), nor is it intended to be recognized as part of his continuity.

Without the augmentation of his brain by his electronic familiar, he can barely function on Splendid Wisdom, the capital of the Empire.

Worse, the traumatic removal has stolen large chunks of his memory, which were never stored in his biological brain.