This Halcyon Classics ebook contains five works by 20th century science fiction writer Clifford Donald Simak. Simak (1904-1988) wrote during the pulp era and during the Golden Age of Science Fiction, achieving a following for his stories based on super science and what he called "realistic fiction."

During his career, Simak received three Hugo awards and one Nebula award, and was named the third Grand Master by the Science Fiction and Fantasy Writers of America in 1977.

This ebook includes an active table of contents for easy navigation.

Empire
Hellhounds of the Cosmos
Project Mastodon
The Street that Wasn’t There
The World that Couldn't Be

This unexpurgated edition contains the complete text, with minor errors and omissions corrected.