When J. Edgar Hoover died in 1972, the New York Times wrote of him, "For nearly a half century, J. Edgar Hoover and the FBI were indistinguishable. That was at once his strength and its weakness." Hoover was a strong personality, fiercely patriotic, and highly organized and controlling. Head of the Federal Bureau of Investigation (FBI) from the presidency of Calvin Coolidge until the presidency of Richard Nixon, he transformed the face of the United States Justice Department and became the definition of law enforcement in America, for better or worse.

John Edgar Hoover was born into a solidly middle class neighborhood in Washington, D.C. His father was in the Coast Guard and later worked as a low-level employee of the federal government. Brought up to the exacting standards of his strict mother, Hoover determined he would surpass his unambitious father. He...