In his near half-century as director of the Federal Bureau of Investigation, J Edgar Hoover made the organisation the domestic anchor of American global power, synchronising the crusades against fascism and communism abroad with the preservation of order and hierarchy at home. Beverly Gage, in the first biography of Hoover in nearly three decades, has tapped into a vast quantity of FBI files and personal papers to produce a vivid study of a man, an institution and a nation.

Hoover’s legacy is largely defined by whom and what he opposed: communism, the Kennedys, Martin Luther King, the New Left. Yet despite his sympathy for conservative causes, Gage argues, ‘the presidents who did the most to empower Hoover were the two great liberal titans of the twentieth century: Franklin Roosevelt and Lyndon Johnson’. In their quests to expand federal authority, they mobilised the forces of warfare as well as welfare. The FBI was the child of the progressive centralisation and expansion of federal power in the 20th century. The New Deal featured a sustained campaign against ‘gangsterism’ and ‘racketeering’, while Johnson’s ‘war on poverty’ was in part intended to reduce crime, which, the president declared, ‘has become a malignant enemy in America’s midst’.

John Edgar Hoover was born in 1895 in Washington, DC. America’s capital was not yet the metropolis it would later become and it existed as a unique island of federal authority in which residents lacked representation or the franchise. Hoover’s family was part of the burgeoning bureaucratic class that