The Dark Tower is a series of seven books written by American author Stephen King between 1970 and 2004. The series incorporates themes from multiple genres, including fantasy fiction, science fantasy, horror and western elements. They describe a Gunslinger and his quest toward a tower whose nature the books call both physical and metaphorical. King has described the series as his magnum opus. Besides the seven novels that compose the series proper, many of his other books relate to the story, introducing concepts and characters that come into play as the series progresses. After the series was finished, a series of prequel comics followed.