The Women’s Murder Club mysteries constitute the longest running of James Patterson’s collaborative series. He and veteran co-author Maxine Paetro have crafted a template that is immediately familiar, but new elements are introduced to keep each installment fresh and unpredictable. Readers coming on board for the first time are never at sea with what has occurred before, while those who have been there from the beginning always find their loyalty rewarded.

That brings us to the newly published 21st BIRTHDAY, a title with multiple meanings. Its prologue begins at the end and then jumps back five months in time to the office of San Francisco Chronicle reporter Cindy Thomas. Cindy, a longtime member of the unofficial but very real Women’s Murder Club, has her office invaded by Kathleen Wyatt, who is not unknown to Cindy. If Kathleen has a penchant for speaking in italics, it is with good reason. Kathleen's 20-year-old daughter, Tara, is missing --- just shy of her 21st birthday --- as is her infant girl, Lorrie. Kathleen is convinced that Tara’s husband, Lucas, is responsible for their disappearances with accusations that border on hysterics. But that does not mean she is wrong.

"In many ways, 21st BIRTHDAY is the best volume in this fine series thus far. It features the unique plotting and skillfully written presentation that Patterson and Paetro have brought to it since their collaboration began."

Cindy hands Kathleen off to Detective Lindsay Boxer just as there is a change in the hierarchy of Lindsay’s division, causing a domino effect in her life going forward. At first Lindsay cannot handle the case because she deals with homicides, and there isn’t a body. That changes, and she starts investigating what appears to be a serial killer at work, even as Tara and her baby are still missing. The murders have a potential tie to Lucas, though medical examiner Claire Washburn helps to avoid a rush to judgment.

Lucas is certainly a prime suspect, though. A teacher at a local private high school, he is in his 40s and likes his dates and his wives to be legal, if barely so. He even had his next spouse all picked out even before Tara and Lorrie disappeared. When an additional pair of tragic discoveries take place, he is charged with murder. Assistant District Attorney Yuki Castellano is tasked with the case. Lucas has a questionable alibi, but also offers a separate SODDI defense --- “some other dude did it” --- which rocks both the investigation and the trial. Lindsay is duty-bound to investigate Lucas’ story, which seems false; if true, it could have implications far beyond San Francisco. The truth eventually comes out and will linger with the reader long after the final sentence is presented.

In many ways, 21st BIRTHDAY is the best volume in this fine series thus far. It features the unique plotting and skillfully written presentation that Patterson and Paetro have brought to it since their collaboration began. As with the books that have gone before, it is a wild ride that leaves the reader hungry for the next one.