I have read all 4 Patrick Bowers novels and have enjoyed them a great deal. The author does a marvelous job and the story is quite intelligent and really clips along.
The single criticism I have is that (semi-spoiler!) the book has yet another villian who is 12 steps ahead of Bowers and is able to orchestrate & execute a complex series of events to lead to the desired conclusion. Quite simply, it strained credulity particularly when similar devices were part of the earlier books in the series.
The character of Tessa and her relationship with Patrick is terrific and the author shines in making them seem genuine.