Keith Laumer 
The Walls [EPUB ebook] 

Four walls do not a prison make, unless they look out upon a world that doesn’t exist any more. Keith Laumer was a Hugo and Nebula award nominee! Before becoming a science fiction writer Laumer was an officer in the United States Air Force and a diplomat in the Foreign Service, adding a note of realism to many of his stories. One of science fiction’s true luminaries.