Kathleen Mallory was an 11-year-old thief living on the streets of New York City when she was rescued/adopted and raised against her will by Detective Louis Markowitz and his wife. She is an intense creature who lacks socialization skills and must be taught a set of rules by which to live. Mallory learns the basic social morés but lives with her own ideas of how the world works and how the world sees (or doesn't see her). She is a savant when it comes to computers and hacking. She has a multitude of secrets and pain, kept well hidden/compartmentalized, even from her closest comrades. O'Connell rounds Mallory out with a cast of extremely well developed, compelling characters.
If you've not read any of O'Connell's work, start with Mallory's Oracle. While some may think that Kathy Mallory comes across a little stiff in this first novel, you'll get hooked - especially if you liked Lisbeth Salander. With each book, a little more of Mallory's past is revealed, and with each revelation her character becomes more compelling. There are currently nine books in the series, with a 10th coming out in January of 2012. You'll want to read them in order:
- Mallory's Oracle (Putnam, Aug. 17, 1994) *50,000 first printings.
- The Man Who Cast Two Shadows (Putnam, June 1, 1995) aka The Man Who Lied to Women (Hutchinson, U.K. 1995)
- Killing Critics (Putnam, June 18, 1996)
- Stone Angel (Putnam, July 14, 1997) aka Flight of the Stone Angel (Hutchinson, U.K.)
- Shell Game (Putnam, July 5, 1999) aka Magic Men (Hutchinson, U.K.)
- Crime School (Putnam, Sept. 12, 2002)
- Dead Famous (Putnam, Sept. 11, 2003) aka The Jury Must Die (Hutchinson, U.K.)
- Winter House (Putnam, Oct. 21, 2004)
- Find Me (Putnam, Dec. 28, 2006) aka Shark Music (Hutchinson, U.K.)
- The Chalk Girl (January 17, 2012)
O'Connell has also written two stand alone novels, and while Mallory is not present in either of these books, they're both quite good:
- The Judas Child (Putnam, June 15, 1998)
- Bone by Bone (Putnam, Dec. 30, 2008)