Ellroy's second published novel sets the stage for the long-running L.A. "bad cop" Dudley Smith who appears in many of his novels as a foil for several of his principal characters.
His real life mother's murder and Ellroy's childhood receive fictionalized treatment and form the core of the story which does not become apparent until the final third of the novel.
If you don't plan to read all of Ellroy's works you're better off starting with his well-known ones like The Black Dahlia and L.A. Confidential. If you become an Ellroy fan you'll definitely want to read this one.