There's no shortage of serial killer novels in mystery fiction; no lack of dead hooker stories, iconoclastic detective characters or plot synopses that begin "must unravel past crimes..." These are the common, tried-and-true components of stacks of mystery novels, many unremarkable. Carol O'Connell takes these trite and tired old tools, mixes in dark, psychologically complex motivations, unusual and complicated plot lines and wholly original characterizations, throws in some New York attitude, and serves up something vital and new.

First introduced in 'Mallory's Oracle' in 1994, and reappearing in seven subsequent books, Kathy Mallory is a rare and truly original anti-hero - female gender. A homeless street child in New York City, adopted but not tamed by Louis Markowitz, a NY Special Crimes Unit Detective, Mallory is tough, street smart and still feral. She's an intense, wounded survivor, well before "survivor" came to refer to people who would eat live bugs for a chance to win money and be on TV.

O'Connell's Mallory series is characterized by complex psychological themes, embellished by its New York setting and abrasive New York humor, and driven by its intensely independent, still mysterious female protagonist and a strong cast of supporting characters. That Mallory is still enigmatic after seven books and that the supporting cast remains compelling and engrossing is testament to O'Connell's superb skill as a storyteller and her ability to create unique and highly original characters.

In 'Crime School', the Special Crimes Unit is called to investigate the grisly death-by-hanging of a New York call girl, a woman Mallory recognizes from her past. Sparrow, the dying hooker, once befriended and protected the lonely, green-eyed Mallory-child as she roamed the NY streets. She also once betrayed that child, and for Mallory, that betrayal demands retribution. The crime scene too -- a hanging death, the victim's chopped off hair dangling from her mouth, a smoldering fire and imported dead flies -- harkens back to the past, to a case investigated by Louis Markowitz some twenty years earlier. That case involved a street urchin, a grisly death, fire and an enigmatic ending. A subsequent murder, with the same characteristics, sets Mallory and the Special Crimes Unit to unraveling the past in search of a serial killer, a copycat killer, or both.

Central to solving the mystery is a series of cheap western paperbacks featuring Sheriff Peety and the Witchita Kid, books read to Mallory by the hookers of the East Village -- the Hooker Book Salon. Neither the hookers nor Mallory read the last book; none knew how the series ended. But a rare copy of that last book was found next to Sparrow in the opening crime scene. The books, the hookers, the solution to the killings past and present, all unite to provide a page-turning mystery and some long awaited insight into Mallory's history.

O'Connell can plot with the best contemporary mystery writers; she twists, turns, layers, whipsaws and surprises with ease and skill. But at their core, O'Connell writes character-driven narratives. Her ability to mine the depths of psychological motivations elevates these otherwise simply great stories to levels of searing intensity and surprising passion. And no character is more compelling, more psychologically rich, than Mallory herself, a true mental minefield ready to explode at the least expected spark. We know she's sophisticated, stylishly Armani-clad and uncommonly beautiful. She's frightenly smart, street and systems savvy, and ferociously independent. She's also rude, abrupt, often insensitive and frequently vicious. She can pick locks in the flash, steal whatever needs stealing, and blow away, with a glance or a gun, those in her way, be they hookers, pimps or superiors. And you can easily believe that the glance-or-gun choice, for Mallory, is a toss-up. O'Connell doles out details of Mallory's childhood street life and battered psyche like breadcrumbs and infrequently lets the reader inside her head to view her motivations. What we know about Mallory we learn from what she does, not what she says, and from the actions, reactions and speculations of the cast of recurring supporting characters. It's an unusually passive approach to creating an absorbingly active character, and a tantalizing one. Readers willingly follow O'Connell's breadcrumb trail in search of insight and understanding.

The supporting characters in the Mallory books are both crucial to the series' success, simply wonderful -- and they're all male. Mallory's business partner, Charles Butler, is an ungainly, cultured, wealthy and over-educated anachronism. Ever ready to assist Mallory, apparently ever immune to her icy self-involvement and penchant for danger, Bulter is the anti-sidekick to Mallory's antihero. He's most definitely just this side of foppish, but endearing and slightly wistful, and he contributes an essential cerebral element to balance Mallory's bravado. Detective Riker, former partner of Mallory's adoptive father Markowitz, now partnering Mallory, is the classic hardened cop, honorable but scarred, in love with his ex wife and prone to lonely alcoholic binges. He's also the guardian of much Mallory lore, which he dispenses sparingly in the form of an occasional story from the past. All the men surrounding Mallory are alternately in awe of her, intimidated by her, a little or a lot in love with her, or, quite frequently, simply terrified of her.

O'Connell's stories never end where you expect them to end. Denouements are followed by new revelations, solutions followed by new puzzles. Near the end of 'Crime Story', after the killer has been apprehended, Ricker tells Butler the full story of Mallory and Sparrow's relationship of twenty years prior. Readers satiated by the resolution of a complex crime and secure that all is now right with the world, are slapped into shock with a story so intense, so revealing and so achingly sad it could anchor yet another novel. O'Connell needn't worry about readers coming back. She builds anticipation into each book by writing engrossing and enigmatic novels and then dangling a tantalizing lure at the end.

All series mysteries are best read in chronological order, and this is particularly true of the Mallory novels. Readers will find the stories, and particularly the Mallory character, are best savored in sequence. O'Connell's newest Mallory book, 'Dead Famous' has just been released in hardcover. It's going in my vault of blue-chip reads, to be saved for the proverbial rainy day.