Slaughterhouse-Five is a science fiction novel by Kurt Vonnegut. It follows the life of Billy Pilgrim, a World War II soldier who becomes unstuck in time and experiences his life out of chronological order. Through Billy's journey, the book explores the horrors of war, the concept of free will, and the nature of human existence. Vonnegut's unique blend of science fiction and dark humor makes this book a must-read for fans of the genre.