This volume assembles four of Clifford D. Simak"s classic short works into one volume, plus a lengthy introduction to the author and his work. Included are: "Hellhounds of the Cosmos" (in which invaders from the fourth dimension ravage the Earth), "The World that Couldn"t Be" (in which a farmer on an alien world tried to hunt down the creature destroying his crops -- only to find himself the prey), "The Street that Wasn"t There" (written with Carl Jacobi -- in which an entire street mysterious vanishes), and "Project Mastodon" (in which time travellers stuck in the past come up with an ingenious plan). Great pulp science fiction from a master!