The Dark Tower is a series of seven books by American writer Stephen King. The series begins, “The man in black fled across the desert, and the gunslinger followed.” It tells the story of the last living member of the Gunslingers, Roland Deschain, and his quest to catch The Man in Black, which will ultimately lead him to the Dark Tower. The Dark Tower is often described in the novels as a metaphor, and also as a real structure said to be located at the nexus of all universes. Roland exists in a place where “the world has moved on”, in a world that is recognizable as the Old West but exists in an alternate time frame or parallel universe to our own. The series incorporates themes from multiple genres, including fantasy fiction, science fantasy, horror, and western elements. King has described the series as his magnum opus; beside the seven novels that comprise the series proper, many of his other books are related to the story, introducing concepts and characters that come into play as the series progresses.
Site – http://www.stephenking.com