A seminal figure of twentieth-century science fiction, Philip K. Dick ponders the very nature of humanity in this anthology of five gripping short stories and novellas that were first published in early 1950s pulp magazines. Written during the Cold War, “The Defenders” presents a tale of robotic warfare. “Foster, You’re Dead” criticizes consumerism and the Cold War, when the military-industrial complex shifted responsibility for self-defense to families by selling bomb shelters. “Piper in the Woods” is a clever short story concerning the erosion of reality. A military psychologist is tasked with solving the mystery of why military personnel are behaving like plants upon their return from an asteroid. “Second Variety” is prescient in its anticipation of the hazards of self-evolving robots that can operate independently of one another. In “The Variable Man,” Earth relies on computer technology and a time traveler to...