The Maltese Falcon
by Dashiell Hammett
Sam Spade is a private detective in San Francisco during the 1910's or 1920's. The action starts when "Miss Wonderly" hires Spade's partner to tail somebody. As the story unfolds, Miss Wonderly's story continues to change, and people are killed. A treasure is at stake, and Spade must navigate the treacherous dealings of all involved.
This is widely considered a classic. It was different from most books I've read because the narrator stuck strictly to the facts. The narrator only described setting and told you what people said. The narrator did not give any special insight into any of the character's thoughts and feelings. This leaves a lot to the imagination, but it can also be frustrating. You are always left guessing as to what is really going on in the characters' hearts and minds.