"The Gunslinger" is the first chapter of Stephen King's The Gunslinger, the first chapter of all "The Dark Tower" story.
The chapter is all narrated backwards: it starts with Roland's hostage at Brown's house. Roland tells him about his journey through Tull, then the narrative goes back to the events that have occurred in the city. In Tull, Roland came looking for the Man in Black, who was there, but he was gone before Roland arrived. After a succession of events, Roland shoots every inhabitant of the city, after they were urged by Sylvia Pittston. The story returns to Brown's house. Roland continues his journey walking alone, for his mule died during the night he stayed there.