I had an interesting experience with this book: I somehow did not realize until about halfway through it that it was nonfiction. It was fascinating to see how my expectations for it shifted.
What is the difference between fiction and nonfiction? Clearly, it extends past fact and fantasy. If this were fiction, it would feel sloppy; characters' storylines don't draw together like they're supposed to, there's no exciting twist near the end, and we don't ever find out what "really happened" that fateful night.
As nonfiction, all the characters don't have to come together by the end. Lady Chablis and Joe Odom, two of the three primary characters in the first half of the book, don't have to have anything to do with each other or the third main character, Jim Williams, and his four murder trials. The four murder trials don't have to be markedly different; they are spectacular enough in that they actually happened at all.
Another difference. Early on in the book, the narrator introduces an intriguing enigma: Williams possesses a Nazi flag and several german pistols. If this were fiction, that would eventually, even inevitably, lead to some revelation of dark and bizaare Nazi history. As nonfiction, it simply stays enigma, and that's okay: the world is weird, and little things don't always lead to big things.
People like to say that truth is stranger than fiction, and I would imagine that some would cite the bizaare story in this book as evidence. However, what I'm learning is that we have very different expectationsof truth and fiction -- what makes a wonderful nonfiction account of truly bizaare people and events would, in all honesty, make pretty tepid and sloppy fiction.