The T-26 was the first major Soviet armour program of the 1930s, beginning as a license-built version of the British Vickers 6-ton export tank. Although the T-26 retained the basic Vickers hull and suspension, the Red Army began to make extensive changes to the turret and armament, starting with the addition of a 45mm tank gun in 1933. The T-26 was built in larger numbers than any other tank prior to World War II. Indeed, more T-26 tanks were manufactured than the combined tank production of Germany, France, Britain, and the United States in 1931–40. This book surveys the development of the T-26 as well as its combat record in the Spanish Civil War, the war in China, the border wars with Poland and Finland in 1939–40, and the disastrous battles of 1941 during Operation Barbarossa.