The Mephisto Club is the sixth mystery in this series featuring Boston detective Jane Rizzoli and medical examiner Maura Isles, this time on the case of the brutal murder of a young woman on Christmas Eve. Though both women participate in the investigation, Jane plays a much larger role than Maura in the book.

The crime, and a subsequent murder, is quickly linked to an unusual group of wealthy individuals who are members of the Mephisto Club, an organization that seeks out evil in the world. The group is headed by a mysterious and powerful man with the highest level connections, giving him access to confidential information on the victims and the crimes. Though apparently working on the same side as the officials investigating the murder, it's not clear his objectives are the same. Is he part of the solution or part of the problem?

The Mephisto Club has a solid, effective, fast-paced plot with a number of unusual features that make it an above-average thriller. The incorporation of obscure symbolism and the inclusion of arcane biblical references make the, at times, implausible storyline quite credible.

There are a few problems, however, that prevent The Mephisto Club from being first-rate. In an effort to show the familial side of both Jane and Maura, Gerritsen includes two side stories that seem incongruous. For Jane, there are the droll scenes with her parents that seem to be present solely for comic relief. For Maura, it's her troubled relationship with Father Brophy. Neither seems terribly important for this book, but may simply have been included for the purpose of continuity of the series.

A more serious problem is the motivation of the culprit and the purpose for the murders. Though it appears to be personal, in the end, the implication is that there was an ulterior motive to the crimes that is at odds with the events that took place. It's rather convenient how it all turns out, and just a bit illogical.

Despite these few shortcomings, The Mephisto Club is definitely worth adding to your library.