As an series progresses, it is natural for writers to simply run out of directions in which to take characters and out of situations in which to put them. It seems perhaps Finch has reached that point - and perhaps (given the references that Charles Lennox is contemplating hanging up his hat) he knows it. I hope not.
The story opens slowly, with Lennox asked to temporarily leave Britain in order for the Prime Minister to avoid being put in a difficult place politically after an investigation by Lennox uncovered police corruption at the highest levels. As a result, Lennox takes leave for a tour of America - but he is waylaid in Providence, RI: the domain of America's aristocracy, the rising "robber barons." Lennox's experiences (and Finch's observations) about America generally and the lifestyle of the robber barons specifically is excellent. The details in behavior, address and of course extravagance and opulence made for lively reading. The investigation was, sadly, mediocre when compared to his earlier work. While the red herrings and suspects were plausible, a close reading quickly provided the critical clues to close the case relatively quickly. The resolution and conclusion seemed to indicate (as mentioned earlier) that perhaps this is the last we'll see of Charles Lennox. Of course, this notion has crossed Lennox's mind before, so it too may be a ruse.
While compared to his earlier work this isn't quite up to snuff, Finch's attention to detail of setting and character make up for what is a middling mystery. Still and all, recommended.