Book excerpt: In this powerful memoir about three generations of New York City policemen, Brian McDonald chronicles a hundred years of dedication, disillusion, heroism, and tragedy behind the blue wall of silence that separates a cop from the rest of the world. His grandfather, Thomas Skelly, entered the department in 1893, when the NYPD was little more than a brutal gang of organized enforcers and Tammany Hall a corrupt political machine that could make or break an honest cop's career. His father Frank's career would span World War II through the 1960s, taking him from street cop to squad commander of the Forty-first Precinct. Better known as "Fort Apache", it was a place from which few cops emerged whole. His brother Frank McDonald, Jr., went on to become a decorated officer, waging an undercover war on drugs and crime. From turn-of-the-century Brooklyn to the South Bronx in the 1970s to the bedroom communities of upstate New York, My Father's Gun combines a rare and intimate family story with turbulent social history.