While nominally fantasy, this series is a mix of fantasy, sci-fi, western, and mystery. The series is seven books long, not counting the short stories, so for the purposes of our meeting, we'll just be reading book #1, as seven books is a little more commitment than we can reasonably expect from people.
A brief synopsis: The Gunslinger introduces protagonist Roland as he pursues the Man in Black through bleak and tired landscapes in a world that has "moved on." Roland believes that the Man in Black knows and can be made to reveal the secrets of the Dark Tower, which is the ultimate goal of Roland's quest. The Waste Lands sees Roland and his fellow travelers continuing the quest for the Dark Tower. They journey through imaginative landscapes, over astounding obstacles, and meet with and confront a unique and fully drawn cast of characters, both human and nonhuman.