The Case of the Gilded Lies by Earl Staley Gardner

The ingredients were quite one middle-aged tycoon with a lovely young wife; one oh-so-apologetic visitor to the tycoon's office; one devoted secretary, graduate of a correspondence course of How to Be a Detective. But when these ingredients were combined and brought to the boil with the addition of one inflammable blonde - the result was murder. And when Perry Mason was called in to clean up the kitchen, he found that too many cooks almost spoiled the broth.