Isaac Asimov's "Foundation Trilogy" is a series of science fiction novels that explores the rise and fall of a galactic empire. The story follows the efforts of Hari Seldon, a mathematician who develops a theory called psychohistory, which uses statistical laws to predict the future of large populations. Seldon establishes the Foundation, a group tasked with preserving knowledge and culture to shorten the impending dark age. The trilogy consists of three main books: "Foundation," "Foundation and Empire," and "Second Foundation." Asimov delves into themes of power, knowledge, and the cyclical nature of history. The series has had a significant impact on the science fiction genre and inspired many subsequent works.