I have read Red Harvest a number of times. Here's my review:
The great grand-daddy of all crime novels, Red Harvest was Dashiell Hammett's first commercial success, and laid the ground work for his later novels such as The Thin Man and The Maltese Falcon. It created a new genre of protagonist, the hard-boiled, quick-tongued, and street-smart man who got by on a combination of wits and near-prescience.
Red Harvest was by legend the inspiration for Akira Kurasawa's Yojimbo. While this has never been confirmed, it seems obvious by the themes explored. That film was later made into Last Man Standing starring Bruce Willis, although by then the story bore little resemblance to the original. The idea of playing both sides of a political struggle to one's own ends was retained throughout the generations of film.
The original story follows the efforts of an un-named protagonist working for the Continental Detective Agency of San Francisco, told in first person. He has been summoned to the small western industrial town of Personville to assist in the dealings of a local banker, discovering upon arrival that his employer has been murdered. Discovering the motivation behind the murder also uncovers the criminal dealings of "Poisonville," a situation that both demands results and offers the protagonist a chance to accomplish more than anyone expected.
Naturally, the murder is only the tip of the iceberg, and involves two gangs as well as a corrupt police department. Allying himself with whomever is convenient at the time, the "Continental Op" works to uncover the truth while avoiding constant threats on his life.
Thoroughly enjoyable and addicting, Red Harvest is a great read for anyone who wonders where the detective genre came from and the resultant glut of films and jargon. The protagonist may seem unrealistic, but one must keep in mind that Hammett based this story on his time spent as a union-buster for the Pinkerton Detective Agency after World War 1.