Foundation and Chaos (1998) is a science fiction novel by Greg Bear, set in Isaac Asimov's Foundation universe.

The novel is the second part of The Second Foundation Trilogy and takes place almost entirely in the same time frame as the "The Psychohistorians", which is the first part of the novel Foundation. In addition to telling a more expanded version of Hari Seldon's confrontation with the Commission of Public Safety it also interweaves R. Daneel Olivaw's struggle against a sect of robots who oppose his plans for humanity.