The Dark Tower (Book 1): The Gunslinger by Stephen King was published as five short stories between the years of 1978-1981. The five stories were assembled into novel form in 1982 and was then revised in 2003.
Roland, a gunslinger, seeks a mysterious wizard known only as 'The Man in Black.' Allong the way, Roland meets a young boy named Jake Chambers, who claims he's from 1972 New York City. The gunslinger takes Jake along,Roland fears Jake was placed in his path as a trap.
"The Man in Black fled across the desert and the Gunslinger followed." This iconic line starts this novel and the entire Dark Tower series. I've read this one repeated. It's gritty, action-packed and just plain addictive. I've read all seven and went back for the 4.5 addition published in 2012.