Clifford Donald Simak (1904 - 1988) was an American science fiction writer. He was honored by fans with three Hugo Awards and by colleagues with one Nebula Award. The Science Fiction Writers of America made him its third SFWA Grand Master and the Horror Writers Association made him one of three inaugural winners of the Bram Stoker Award for Lifetime Achievement. In this book: Empire Hellhounds of the Cosmos The World That Couldn't Be Project Mastodon