Although Kurt Vonnegut Jr.'s renowned refrain, "And so it goes", appears over 100 times in the novel, it it is not uttered even once in this film.
Kurt Vonnegut Jr., author of the book this film was adapted from, was a prisoner of war in World War II. He was captured during the Battle of the Bulge while a battalion scout with the 106 Infantry Division on December 22, 1944, and used these experiences in his novel when Billy Pilgrim is captured by the Germans and sent to a POW camp. Vonnegut also lived through the bombing of Dresden and used that experience in the book.
Author Kurt Vonnegut Jr. would later write: "I love George Roy Hill and Universal Pictures, who made a flawless translation of my novel."
The character of Howard Campbell Jr. appears in the film and speaks to the American POWs before the bombing of Dresden. Kurt Vonnegut Jr. wrote an entire novel about this character called "Mother Night", later made into a film by Keith Gordon starring Nick Nolte as this same character.
In an early scene when Billy's mother is visiting him in the hospital, she is talking about Billy's Dresden experience to Elliot Rosewater - the title character from Kurt Vonnegut Jr.'s 1965 novel, "God Bless You Mr. Rosewater", and a character who was later portrayed by Ken Hudson Campbell in 'Breakfast of Champions (1999)'.