Marcus Didius Falco is a hard-boiled private eye during 1st century Rome. He comes from a plebeian background but is married to an aristocrat, the daughter of a senator. If you've seen The Thin Man with William Powell and Myrna Loy you have an idea of the relationship.
This is the 3rd or 4th book in the series that I've read, and about the 18th in the series overall. The ones I've read have been entertaining. Not nearly as historically interesting as the Steven Saylor Gordianus series, but good solid entertainment. The Falco character is raffish, tough, smart, outspoken, and self-deprecating.
The author makes a point of having her characters speak in slang, some of it made-up for the purpose. The result feels like Chicago in the '20s, and maybe that's appropriate. Rome was a pretty rough-and-tumble place, a huge cosmopolitan city, corrupt at all levels, and violent in a way that would be familiar to big-city residents in America.