The Brass Cupcake is John D. MacDonald's debut novel, and it provides a template for many of the others that would follow. The protagonist is a guy named Cliff Bartells, who might serve as an early version of MacDonald's great series hero, Travis McGee. Bartells was on the police force of the town of Florence City, Florida, but he was basically driven off the force for being too honest. Unlike virtually every other member of the city's totally corrupt police department, he refused to take bribes from the local mobsters for looking away from their illegal activities.
Bartells now works as a claims adjustor for an insurance company. When an elderly woman, visiting Florence City from Boston, is murdered and robbed of $750,000 worth of jewelry insured by Bartell's company, it's his job to get it back. This is somewhat familiar territory for Bartells in which professional thieves rip off somebody's jewels, then use underworld connections to contact the insurance company and sell the jewels back for a fraction of the amount for which they were insured.
Bartells has been the middleman in these sorts of transactions before, but this time it's different because there's a murder involved. Professional thieves don't usually murder people and it throws off the whole equation and makes Bartell's job that much harder and infinitely more dangerous. The local cops, who still hate Bartells, don't want him mucking around in their investigation, and Bartells must also contend with the beautiful blonde heiress who stands to inherit the murdered woman's estate. And, of course, there are a number of other shifty and inscrutable characters as well.
Municipal corruption was a standard theme in a lot of MacDonald's books, most of which are populated by tough, relatively incorruptible protagonists like Cliff Bartells who may bend the rules here and there, but always in the service of a good cause. It's always fun to watch someone like Bartells come up against bad guys of various stripes in MacDonald's novels, and this book sets a high standard in that regard.
As is the case with a lot of MacDonald's work, read forty or fifty (or in this case, seventy) years down the road, some of the sex scenes are pretty awful, and the treatment of the female characters is at times cringe-worthy. Still, this is an excellent hard-boiled novel, and it's very much a book of its time. Over the course of the thirty-five years to follow, MacDonald would write a lot of really great crime novels, and The Brass Cupcake was a great beginning to his career.