The Historical Novel Society reviewed The Ionia Sanction months ago, and I utterly failed to report it here.  I'm correcting that grievous fault now.  Here's what they had to say:

Athens, 5th century B.C.: Nicolaos is an investigator for hire, which is not so strange considering this is the city that invented the professional philosopher. Fresh off his last case in The Pericles Commission, Nico (if I may be familiar) has another politically charged murder to solve. This time the investigation takes him to Ephesus, where he uncovers a Persian plot to conquer Athens. 

The action is solidly paced and engaging throughout, while Nico’s noir-ish patter makes the history highly accessible. And there is a lot of history; every major figure gets a mention, including an irritating little brat named Socrates who happens to be Nico’s kid brother. 

Corby weaves in most of these historical nuggets skillfully, and a few that at first appear to be one-off mentions end up being quite relevant to the plot. There are also some very amusing, if slightly anachronistic, jabs at modern times when Nico struggles with concepts such as trousers (a Persian innovation), and mercantilism (“You mean I could come here with a bit of money…buy something I didn’t make myself… and I’d make a profit?”) But Corby succeeds best when he shows us the subtle little nuances of the era. Moments such as Nico’s impromptu – and very touching – sacrifice to Artemis show us that he’s a lot more than Sam Spade in a chitoniskos. He’s a man of a different and very intriguing era, and he’s worth reading.