The name Dennis Lehane probably rings a bell since he is the author of Mystic River and Shutter Island. This one is a Kenzie and Gennaro series book, a series which I've never read but I sure did love this book.
I think the major reason I enjoyed it so much is that he can give you a character you would recognize in a minute. Like this description of a girl working the counter at a diner: "She was about nineteen. A pretty face had been damaged by acne scars and she wore an extra forty pounds on her frame like a threat. Her eyes were dull with anger disguised as apathy. If she kept on her current path, she'd grow into the type of person who fed her kids Doritos for breakfast and puchased angry bumper stickers with lots of exclamation points." Can't you just see her? And this is an extremely minor character, so imagine what he does with someone important to the story.
The story is set in Boston which is what attracted me to this library book to begin with. I know Boston well enough to recognize places where characters are, and I know what people there are like well enough to recognize that he has them down cold. I haven't felt like I was in the Boston area like this since Robert B. Parker left us.
The protagonist, Patrick Kenzie, had found a girl named Amanda many years earlier but her "rescue" didn't exactly work out well because she was returned to a stupid, drug addled, neglectful mother. Now she's 16 years old and in trouble. Her aunt comes to Patrick to ask for help and he just can't refuse because he feels guilty about what happened before. Meanwhile, he and his wife have had a little girl who is immensely entertaining to the reader, but would drive you crazy in real life. Add some Russian goons to the mix and you have a wild and crazy ride.
I was hooked on the story right from the start and surprised at the end. That and great characters are the epitome of a good crime book to me and I recommend this one.