Based on his experiences as a POW during the Allied bombing of Dresden in 1945, Kurt Vonnegut's Slaughterhouse-Five is (rightfully) considered a modern literary masterpiece. It propelled Vonnegut, who had been largely ignored and classified as a sci-fi paperback writer, to fame and literary acclaim.

The novel follows Billy Pilgrim, a man who has become "unstuck in time," and weaves together different periods of his life—his time as a hapless soldier, his post-war optometry career, and a foray in an alien zoo where he served as an exhibit—with humor and profundity. "The dominant theme of what I have written during the past forty-five years or so,” Vonnegut wrote in 1994, “is the inhumanity of many of man’s inventions to man.”

Here are 15 things you may not have known about this 1969 classic (not that the dates matter to Tralfamadorians):

1. After repeated and failed attempts to start his "Dresden book," Vonnegut finally began what would become Slaughterhouse-Five during a two-year teaching stint at the University of Iowa Writers’ Workshop. He had stopped writing fiction and was in a considerable funk when he accepted the invitation, offered by his former editor George Starbuck who was a full-time professor of English at the university.

2. He credits the program for rekindling his love of literature. "At Iowa I was suddenly friends with Nelson Algren and Jose Donoso and Vance Bourjaily and Donald Justice...and was amazed. Suddenly writing seemed very important again. This was better than a transplant of monkey glands for a man my age." He also became friends with Richard Yates while there, and some of his students included Gail Godwin, John Irving, Jonathan Penner, Bruce Dobler, John Casey, and Jane Casey.

3. Impressed by the book reviews Vonnegut wrote during his hiatus from fiction, publisher Seymour Lawrence offered Vonnegut a $25,000 advance to work on his Dresden book (and two other novels) full-time.

4. Published on March 31, 1969, Slaughterhouse-Five became an instant and surprise hit. It spent sixteen weeks on the New York Times best seller list and went through five printings by July.

5. The novel owes much of its immediate success to two rave reviews; one in the New York Times Book Review, which was featured on the section's front page, and another in the Saturday Review.

6. Robert Scholes, who wrote the Times review, was a colleague of Vonnegut's at Iowa. As Jerome Kinkowitz writes in The Vonnegut Effect, “A correlation exists between the first two major reviews of Slaughterhouse-Five: each was written by a critic who had heard Vonnegut speak to audiences, and who had been, moreover, impressed by the personal voice in the author’s fictive statement. Not that public speaking was Vonnegut’s chosen profession; rather, his talk at Notre Dame University’s Literary Festival (as heard by Granville Hicks) and his two-year lectureship at the University of Iowa (where Robert Scholes was a colleague) were stopgap measures to generate some income after his customary publishing markets had either closed or ceased to respond."

7. Slaughterhouse-Five was banned from Oakland County, Michigan public schools in 1972. The circuit judge there accused the novel of being “depraved, immoral, psychotic, vulgar, and anti-Christian.” In 1973, a school board in North Dakota immolated 32 copies of the book in the high school's coal burner.

“My books are being thrown out of school libraries all over the country—because they’re supposedly obscene," Vonnegut told the Paris Review. "I’ve seen letters to small-town newspapers that put Slaughterhouse-Five in the same class with Deep Throat and Hustler magazine. How could anybody masturbate to Slaughterhouse-Five?”

8. Slaughterhouse-Five is still being banned in schools. In 2011, Wesley Scroggins, an assistant professor at Missouri State University, called on the Republic, MO school board to ban Vonnegut's novel. He wrote in the local paper, “This is a book that contains so much profane language, it would make a sailor blush with shame. The ‘f word’ is plastered on almost every other page. The content ranges from naked men and women in cages together so that others can watch them having sex to God telling people that they better not mess with his loser, bum of a son, named Jesus Christ.” The board eventually voted 4-0 to remove the novel from the high school curriculum and its library.

9. In response to this ban, the Kurt Vonnegut Memorial Library in Indianapolis gave away 150 free copies of Slaughterhouse-Five to Republic, Missouri students who wanted to read it.

10. The American Library Association listed the book as the 46th most banned or challenged book of the first decade of the 21st century.

11. A film adaptation of Slaughterhouse-Five directed by George Roy Hill and starring Michael Sacks as Billy Pilgrim was produced in 1972. Vonnegut called it "flawless."

12. The character "Wild Bob" is based on William Joseph Cody Garlow, grandson of Buffalo Bill Cody and commander of the 423rd regiment in World War II. A private in that regiment, Vonnegut was captured along with Garlow on December 19, 1944 at the Battle of the Bulge.

13. While Vonnegut fills the novel with non-fiction asides and excerpts from real accounts, the pornographic postcard carried around by Roland Weary depicting a woman with a pony flanked by doric columns is non-existent; the story of the photographer André Le Fèvre is completely fictionalized. However, the name "André Le Fèvre" may come from André Lefèvre, a famous French scoutmaster—the equivalent of a Boy Scout leader.

14. In a "Special Message" written for the Franklin Library's limited edition of Slaughterhouse-Five, Vonnegut writes, “The Dresden atrocity, tremendously expensive and meticulously planned, was so meaningless, finally, that only one person on the entire planet got any benefit from it. I am that person. I wrote this book, which earned a lot of money for me and made my reputation, such as it is... One way or another, I got two or three dollars for every person killed. Some business I’m in.”

15. "So it goes," the book's melancholic refrain, appears in the text 106 times.