Red Harvest
Hammett wrote The Maltese Falcon, which became a great movie, and The Thin Man, which spawned one of the first movie franchises, but this is his great novel.
An operative of the Continental Agency (we never learn his name) is dispatched to Personville, California, a small city. People in the know call it Poisonville. His client is murdered before they can meet, and we begin single-handedly to wrest the town from the control of an unsavory league of industrial goons, booze smugglers, beer distributors, and a police department they jointly own. In the middle of everything is Dinah Brand, a woman whom everyone loves: the long line of her lovers soon includes the Continental Op, but that doesn’t change his plans.
The body count is formidable, so high in fact that at one point the investigator himself goggles at the total. So many characters die so quickly that Hammett has a hell of a time helping us keep everyone straight. This is the novel that changed American mysteries and from which film noir springs.
It ought to have been the start of a long line of books. Whiskey and Hollywood got in the way, but we’ll always have Poisonville.