After years of struggle, the Foundation lies in ruins—destroyed by the mutant mind power of the Mule. But it is rumored that there is a Second Foundation hidden somewhere at the end of the Galaxy, established to preserve the knowledge of mankind through the long centuries of barbarism. The Mule has failed to find it the first time—but now he is certain he knows where it lies. The fate of the Foundation now rests on young Arcadia Darell, only fourteen years old and burdened with a terrible secret. As its scientists gird for a final showdown with the Mule, the survivors of the First Foundation begin their desperate search. They too want the Second Foundation destroyed . . . before it destroys them.

A millennium into the future two advances have altered the course of human history: the colonization of the Galaxy and the creation of the positronic brain. Isaac Asimov's Robot novels chronicle the unlikely partnership between a New York City detective and a humanoid robot who must learn to work together.Detective Elijah Baiey is called to the Spacer world Aurora to solve a bizarre case of roboticide. The prime suspect is a gifted roboticist who had the means, the motive, and the opportunity to commit the crime. There's only one catch: Baley and his positronic partner, R. Daneel Olivaw, must prove the man innocent. For in a case of political intrigue and love between woman and robot gone tragically wrong, there's more at stake than simple justice. This time Baley's career, his life, and Earth's right to pioneer the Galaxy lie in the delicate balance.

The Fourth Science Fiction Megapack selects 25 more modern and classic science fiction stories, by talented authors new and old. Included in this volume: Mary A. Turzillo, E.C. Tubb, Murray Leinster, Theodore Sturgeon, Philip K. Dick, Katherine MacLean, Kurt Vonnegut Jr., Jason Andrew, Larry Hodges, Carmelo Rafala, Ray Cluley, Henry Kuttner, Cynthia Ward, George H. Scithers, John Gregory Betancourt, James C. Stewart, Milton Lesser, John Russell Fearn, Marissa Lingen, Donald A. Wollheim, James K. Moran, Harry Harrison, Edgar Pangborn, Isaac Asimov, and Ayn Rand