The highly successful 'stop-gap' M3 medium tank was designed in 1941, and as adequate turret casting facilities were not yet ready, the M3 used an unusual armament configuration patterned after a French tank. British lend-lease demands led to the design of a second turret type with the US version called the Lee and the British version the Grant. It could penetrate Panzer armor, and its explosive firepower was excellent for dealing with German anti-tank guns. This book covers the design, development, service and variants of a vehicle that was the backbone of many World War II forces.