It is the late 1940s and Frank O'Brian is a gumshoe in New York, in other words a Private Investigator. Having qualified as a lawyer when the US entered WWII, he quit to work as a field agent for the Office of Strategic Services in Europe. On returning to New York he found the notion of returning to the law too tame and hung up his PI shingle. This trilogy of stories consists of The Van Owen Case, The General Simpson Case and The Sandover Twins Case.
Used availability for Paul Henke's The Gumshoe Files