If you haven’t treated yourself to any volumes in the Frank Quinn series by John Lutz, let me be the first to urge you to do so.

Quinn was a homicide detective who now heads Quinn & Associates, a private investigation agency. “Associates” include Pearl Kasner, an ex-bank guard and Quinn’s former (and still erstwhile) love interest, and Larry Fedderman, who was previously Quinn’s police cohort before his own retirement. They make for a prickly team, with Quinn’s residual feelings for Pearl hidden on his sleeve, and a flurry of barbed repartee between Fedderman and Pearl being the exception rather than the rule. Quinn and his investigators are the best at what they do, and as a result are frequently called upon by Police Commissioner Harley Renz to aid the department in a particularly difficult investigation. MISTER X, the fifth and latest Quinn novel, finds the group back in action --- and in danger --- in the most exciting installment of the series to date.

The book gets rolling when Quinn & Associates is asked by Tiffany Keller to reopen an investigation into a series of murders that took place in New York some five years previously. The murderer, known as the Carver, savagely mutilated a number of young women before seemingly dropping off the map and leaving the NYPD with an unsolved and cold case. Tiffany’s twin sisters was one of the victims; after experiencing a small financial windfall, she retains Quinn to obtain closure and to see that justice is done once and for all. Not everyone is happy that these killings are being revisited. Renz, in fact, warns Quinn off the case in no uncertain terms, not wanting a blemish on the NYPD to be reopened for all to see.

Everything changes, though, when a fresh series of murders occur that appear to be related to the original Carver slayings. Renz, ever the political animal, sees a chance to solve a new case and close an old one. He brings Quinn & Associates under his wing once again --- though not without some extracurricular pressure from Quinn --- and opens the NYPD’s resources to them. This includes the highly entertaining and quietly competent Mutt-and-Jeff homicide team of Vitali and Mishkin, as well as a Detroit journalist who may well have been one of the first attempted victims of the Carver and one of the very few to survive his attacks.

There are the twists and turns that one might come to expect from a thriller of this nature. Lutz, however, is a hardboiled veteran of the grammar wars and has forgotten more plot tricks than most authors can remember. Within the final 100 pages, he turns everything his cast of characters knows upside down and sideways, and keeps doing it until he runs out of pages. The result is a book that has everything: a dangerous killer, a pulse-pounding mystery, a shocking solution, and an ending that will resonate with the reader long after the final sentence is read. Oh, and Pearl falls in love, too, but not with Quinn.

It is not necessary to read the first four installments of the series, although you will certainly want to after finishing this new one. Lutz, as he has demonstrated time and again not only with this series but also with his stand-alone works, is capable of scaring the pants off his readers and making them like it. MISTER X is no exception.