How accurate is the historical information in slaughter house five?
This is a rather difficult question to answer, considering the nature of the book. As fiction, we cannot rely on it as an objective account of events. However, Vonnegut based the text on his own personal, actual experiences during WWII, particularly the bombing of Dresden. So there's certainly truth within his story. But like any memoir or personal recount of an historical event, it is an individual perspective: colored with the author's beliefs and point of view. It is, of course, an incomplete view of the events, but accurate for the author nonetheless.