This is Murder / Erle Stanley Gardner

You’re not fooling around with it,” she said, “you’re getting into a game where you’re playing for big stakes and you don’t know what trumps are yet.”

Advertising pays the bills for Sam Moraine, but he can’t help finding it just a trifle dull. So when his poker buddy, district attorney Phil Duncan, is called away to deal with a kidnapping, Moraine is eager to tag along. Little does he realize that he’s about to be drawn into kidnapping, murder, and political corruption—and that his beautiful secretary may  be involved. Moraine wanted excitement, all right, but this might be more than he can handle.