So where did the fleshed-out Mallory come from? Well, in the usual order of things, she began as a little sociopath. The detective’s introduction to the NYPD came at a tender age.

The haunt of Grand Central Station was a small girl with matted hair and dirty clothes. She appeared only in the commuter hours, morning and evening, when the child believed that she could go invisibly among the throng of travelers in crisscrossing foot traffic, as if that incredible face could go anywhere without attracting stares. Concessionaires reached for their phones to call the number on a policeman’s card and say, “She’s back.”

The girl always stood beneath the great arch, pinning her hopes on a tip from a panhandler: Everyone in the world would pass by-so said the smelly old bum-if she could only wait long enough. The child patiently stared into a thousand faces, waiting for a man she had never met. She was certain to know him by his eyes, the same rare color as her own, and he would recognize Kathy’s face as a small copy of her mother’s. Her father would be so happy to see her; this belief was unshakable, for she was a little zealot in the faith of the bastard child.

He never came. Months passed by. She never learned.

Toward the close of this day, the child had a tired, hungry look about her. Hands clenched into fists, she raged against the panhandler, whose fairy tale had trapped her here in the long wait.

At the top of the rush hour, she spotted a familiar face, but it was the wrong one. The fat detective was seen in thin slices between the bodies of travelers. Though he was on the far side of the mezzanine, Kathy fancied that she could hear him huffing and wheezing as he ran toward her. And she waited.

Crouching.

One second, two seconds, three.

When he came within grabbing distance, the game was on-all that passed for sport in the life of a homeless child. She ran for the grand staircase, shooting past him and making the fat man spin. Sneakers streaking, slapping stone, the little blond bullet in blue jeans gained the stairs, feet flying, only alighting on every third step.

Laughing, laughing.

At the top of the stairs, she turned around to see that the chase was done-and so early this time. Her pursuer had reached the bottom step and could not climb another. The fat man was in some pain and out of breath. One hand went to his chest, as if he could stop a heart attack that way.

The little girl mouthed the words, Die, old man.

They locked eyes. His were pleading, hers were hard. And she gave him her famous Gothcha smile.

One day, she would become his prisoner-but not today-and Louis Markowitz would become her foster father. Years later and long after they had learned to care for one another, each time Kathy Mallory gave him this smile, he would check his back pocket to see if his wallet was missing.

So… obviously not one of the more charming sociopaths, the detective rarely feels the need to show her badge in order to gain respect-even in a truck stop:

Mallory carried her tray to the most remote table, aware that all the truck drivers were smiling her way. Their conversations had stopped, and now they stripped her naked with their eyes. They were so fearless in their sense of entitlement-as if they were ticket holders to a strolling peep show. Oh, if eyes could only whoop and holler. She set her knapsack on the table, then removed her denim jacket and draped it over the back of a chair.

“Oh, Lord,” said a passing waitress.

Sans jacket, Mallory displayed a shoulder holster and a.357 Smith & Wesson revolver. With the tight unison of chorus girls, the men turned their faces downward, as if finding their plates infinitely more fascinating.

Problem solved.

Only the waitress seemed to take the gun in stride, shaking her head, as if the lethal weapon might be some minor violation of a dress code.

This gambit has also proved useful in finding parking spaces anywhere in Manhattan and for upgrading hotel rooms elsewhere.

The denim jacket is not part of her usual wardrobe. Shopping at the Gap is Mallory’s idea of going in disguise. On a normal workday, she dresses well beyond the paycheck of a civil servant. In her partner’s opinion, she delights in leaving the impression that she might be a cop on the take. (This passes for a sense of humor in Mallory’s world.) A well-respected art critic once took notice of her outfit.

Though Mr. Quinn could not see the back pocket of her jeans, he knew a designer’s name would be embroidered there. A long black trenchcoat was draped over the shoulders of her blazer, which was cashmere, and her T-shirt was silk. He would have bet his stock portfolio that her curls were styled in a Fifty-seventh Street salon, but not dyed there, for this was that most unusual creature, a natural blonde. In every other aspect of her, a lifetime’s experience in stereotyping had failed him. He could not hazard her occupation or her exact status in the world. And then, as she drew closer, he realized that, if it was true that one could read another’s soul by the eyes-this young woman didn’t have one.

So, she gets on well with truck drivers and art critics, but she is not overly sentimental about children or puppy dogs. And frail little old ladies should never get between Mallory and a case. This is best illustrated with a grand dame of the New York ballet who mistook the young detective for a prospective student of the dance. Madame Burnstien was small and slight, hardly threatening. Her white hair was captured in a bun, and every bit of skin was a crisscross of lines. The only hand visible through the crack of the door was a cluster of arthritic knots wrapped round the cane.

“I’m Mallory. I have an appointment with you.”

“You are Rabbi Kaplan’s young friend?”

Mallory could not immediately place the woman’s accent, but then Anna Kaplan had said that Madame Burnstien hailed from too many countries to call one of them home. In youth, she had danced for the whole earth. Mallory could not believe this crone had ever been young.

“Rabbi Kaplan said you would see me.”

“I said I would look at you, and I have. You’re a beautiful child, but too tall. Go away now.”

The door began to close. Mallory shot one running shoe into the space between the door and its frame. The old woman smiled wickedly and showed Mallory her cane, lifting it in the crack-width to display the carved wolf’s head and its fangs.

“Move your foot, my dear, or you’ll never dance again.”

The cane was rising for a strike.

“Madame Burnstien, you only think I won’t deck you.”

The old eyes widened and gleamed. The smile disappeared and her brows rushed together in an angry scowl as the cane lowered slowly. There was exaggerated petulance in her cracking voice. “I like determination, child, but you waste my time. You’re still too tall.”

“Everybody’s a critic.” Mallory showed her the gold badge and ID. “I want to talk to you about Aubry Gilette.”

“I have many students. Aubry was a thousand dancers ago. What do you expect me to remember about one girl?”

“Oh, I think you remember her better than most. Don’t make me show the autopsy photo. You’re old. It’d probably kill you.”

And she has a grudge against nuns. Well, one nun. Mallory takes great pride in her enemies, and she is particularly proud of Sister Ursula. One night, she interrupted a poker game to ask a case-related question on religion. And here Rabbi David Kaplan points out that she has better sources for Roman Catholic dogma:

“Kathy, as I recall, you had four years of a very expensive Catholic school education. Go and ask Father Brenner. He’s semi-retired now, but I believe he’s filling in the vacation schedule at St. Jude’s this week.”