Slaughterhouse-Five consists of two stories. The main story is about Billy Pilgrim and his memory of the war. It deals with such unrealistic elements as a kind of time warp and extraterrestrials and their four dimensional points of view. These science fictional elements are actually the lies which Billy uses to reduce what Leon Festinger, the social-psychologist, calls "cognitive-dissonance," so that he manages to recollect the war and the air raid on Dresden. This is an indirect way to depict the war and the air raid on Dresden but Vonnegut is very successful in driving the appalling tragedy home to the readers in the 60s. Still, because Billy depends on lies to reduce "cognitive-dissonance," he is too weak to fight against wars in order to protect peace. This is why Vonnegut had to create the other story about the writer who wrote Billy's story, to supply the anti-war attitudes and complement Billy's story.
Discussing such literary techniques as the above, this paper considers how well Slaughterhouse-Five functions as "an anti-war book." It further considers the effects of the Vietnam War on the novel, and a comparison of the novel with other novels on war such as The Naked and the Dead, IF I Die in a Combat Zone, and Catch-22, clarifies what the characteristic features of "an anti-war book" in the 60s are.