Clint Eastwood made this book into a depressing (but good) movie. Unsurprisingly, the book is also depressing (but good), written by one of my favorite authors, Dennis Lehane.
It's set in a dingy blue-collar tight-knit Boston neighborhood, a rat's nest of crime and general dysfunction. A brief opening section is set in 1975, when youngsters Jimmy, Sean, and Dave are engaged in boyish horseplay in the street. A couple predators drive up, pretending to be cops, and bamboozle young Dave into getting into their car; they drive off, leaving Sean and Jimmy vaguely aware that something very bad has happened to their buddy.
Things shift to 25 years later, and the childhood buddies have drifted apart. Dave has (ostensibly) recovered from his childhood trauma; Jimmy, after a brief career as a thief, has been released from the pen and is going straight, with a new wife and some kids; and Sean is a detective with the state police, just coming off a loose-cannon suspension. When Jimmy's daughter is brutally murdered, the twenty-five year old chickens come back to roost.
Lehane is a colorful, evocative writer; practically every page has some pyrotechnic prose that brightly illuminates some bit of character, setting, or plot.