America in the early twentieth century was rife with threats. Organized crime groups like the Mafia, German spies embedded behind enemy lines ahead of World War I, package bombs sent throughout the country, and the 1920 Wall Street bombing dominated headlines. Yet the story of the one man tasked with combating these threats has yet to be told. The Bulldog Detective: William J. Flynn and America's First War Against the Mafia, Spies, and Terrorists is the first book to tell the story of Flynn, the first government official to bring down the powerful Mafia, uncover a sophisticated German spy ring in the United States, and launch a formal war on terrorism on his way to becoming one of the most respected and effective law enforcement officials in American history.

Long before Eliot Ness and the Untouchables went after Al Capone and the Italian mob in Chicago, Flynn dismantled the first Mafia family to exist in America. Next stop for the indefatigable crime fighter would be Chief of the Secret Service where he would set his crosshairs on the country's most notorious currency counterfeiters. Coined "the Bulldog" for his tenacity, Flynn's fame soared as he exposed Kaiser Germany's sophisticated spy and sabotage ring on the cusp of America's entry into World War I. As the Director of the Bureau of Investigation (the forerunner of the FBI), the Bulldog would devise the first counterterrorist strategy in U.S. history. In this riveting biography, author Jeffrey D. Simon brings to life the forgotten saga of one of America's greatest crime and terrorist fighters. Exquisitely researched, The Bulldog Detective finally uncovers the important legacy of this fascinating man who will now no longer be lost in history.