The Continental Op Casebook, Vol. 1

This collection contains nine early stories featuring the Continental Op, an un-named middle-aged detective working for the San Francisco branch of the fictional Continental Detective Agency.
The stories are narrated in the first person. The "hardboiled detective" narrative voice was later used by author Dashiell Hammett in The Maltese Falcon, featuring Sam Spade, and the Thin Man series of stories.