Stalin's Terror of the 1930s has long been a popular subject for historians. However, while for decades, historians were locked in a narrow debate about the degree of central control over the terror process, recent archival research is underpinning new, innovative approaches and opening new perspectives. Historians have begun to explore the roots of the Terror in the heritage of war and mass repression in the late Imperial and early Soviet periods; in the regime's focus not just on former "oppositionists," wreckers and saboteurs, but also on crime and social disorder; and in the common...