Next Door, Next World

Next Door, Next World is a science fiction novel by Robert Donald Locke, written in the early 1960s. The story follows Major Lance Cooper, a space pilot on an interstellar mission aboard the Cosmos XII, as he navigates the psychological effects of hyperspace travel. During his journey, he encounters multiple versions of himself and returns to a reality where his fiancée, Carolyn Sagen, denies her existence. This novel explores themes of identity, love, and the nature of reality through the lens of parallel universes and the human psyche.