The Maltese Falcon, Dashiell Hammett (1929)
Hammett practically invented the detective novel — and the hard-boiled detective himself — with this mystery featuring the iconic Sam Spade. When his partner is killed in a stakeout, the celebrated private eye finds himself at the center of a police investigation. Their mysterious client, known as Miss Wonderly, has disappeared and can't corroborate his story. Once she reappears — and reveals her true identity — he discovers a much deeper plot that involves unscrupulous gangsters and a centuries-old figurine of a bird. Its acclaimed 1941 film adaptation, starring Humphrey Bogart as Spade, is widely considered to be the first film noir.