The Thin Man by Dashiell Hammett (1934) Knopf

A Nick and Nora story wherein Nick, a retired PI, is approached by a young woman to find her father, an inventor and prior client of Nick’s.  He doesn’t want to be involved, but between a scam and getting shot, he decides to pursue the mystery.  Nora is a device to get him to explain, which he avoids until the end.