6) Saturnalia, by Lindsey Davis

Latest in this run of detective novels set during the reign of the emperor Vespasian. After a couple of less impressive efforts in recent years, Davis seems to be firmly back on form: this is an entertaining tale of family dynamics interacting mildly with high politics - Falco is called in to track an escaped German political prisoner, who coincidentally is the former lover of his brother-in-law. Oddly enough the actual murders are the least convincing part of the plot, but the rest is good fun.