This is a collection of Bradbury's very early crime stories, some of his first fiction sales. It comes complete with a short but revealing introduction that explains why the book is dedicated to Leigh Brackett.
One of the stories in the book, "Small Assassin," is likely to be familiar to a lot of readers, but that's the only one. The others, from places like Dime Mystery Magazine and Detective Tales, probably aren't. These aren't great stories, but they're interesting if you care about the development of a young writer who really hit his stride a few years after their publication. Not essential, but certainly worth a little of your time.