"German Field Marshal Von Kleist said, "Their T-34 was the best in the world."  The T-34 tank is legendary as the armored fighting vehicle that won The Great Patriotic War for the Soviet Union.

 In 1931, the Soviet Union purchased two American Christie tanks, which were at the time the most innovative in the world and too advanced for the U.S. Army to get involved with. The main technological advance of the Christie design was the suspension system, which allowed the vehicle to operate at higher speeds over more difficult terrain than the various AFV suspension systems then in use.  This Christie suspension system was incorporated in what became the T-34, and was the most important item in creating the superior fighting vehicle the T-34 was.

 The T-34 was developed in the Kharkiv Tractor Factory in the Ukraine during 1936-37, as a technologically innovative design that addressed the short-comings of the earlier BT series of wheel/track tanks.  These were light tanks designed for very high speed - 53 mph with tracks, and over 60mph in good roads without tracks! - and long range. While these features made a formidable weapon for fast advances deep in enemy territory, the BTs lacked firepower and armor and were not suitable as main battle tanks.

 The prototype - now designated the T-34, was built in early 1939, was tested by successfully driving it 1,000 miles from Kharkiv to Moscow and back. It was put into production in September 1940. The Model 1940 carried the L-11 76.2mm gun, which was shorter than the subsequent 76.2mm main gun of the 1941 and later models. 1,225 T-34s had been produced at the Kharkov Steam-Engine Factory by the time of the German invasion on June 22,

 Besides the suspension, the T-34's main advantage was its  simple design, which made it easy to mass produce and repair. By the middle of the war, with mass production in the Urals factories, a T-34 could be produced in just 40 man hours.  Compared to contemporary medium tanks, the T-34 was smaller and comparably lighter at only 26 tons, while the water-cooled diesel engine minimized the danger of fire and increased the radius of action to 115 miles.

 The design evolved throughout the war: the T-34/76B was equipped with a rolled-plate turret, while the T-34/76C had twin roof hatches instead of the one large hatch, and the T-34/76D introduced a hexagonal turret, with a wider gun mantlet and jettisonable exterior fuel tanks.  The T-34/76E had a cupola on the turret for the commander and all-welded construction, and the  T-34/76F was equipped with a cast-steel rather than welded-steel turret.

 The T-34 first saw action in a series of border battles between Russian and Japanese forces on the Manchurian border in March 1941.  The Japanese reported the outstanding performance of the T-34, but these reports were ignored by the Wehrmacht.

 When the German panzers first met the T-34 in combat, it proved to be a nasty surprise, since it had a more powerful high velocity cannon that placed more emphasis on tank killing ability than did the German Pzkw IV which was the heaviest German AFV at the time, and a higher top speed - 32 mph versus 25 mph.  Additionally, its sloped armor and welded construction was superior to its opponent, while its extra-wide tracks improved cross-country mobility in the great battles on the Russian steppes. The T-34 was so superior to what the Germans had that an emergency program was put in place to create a tank that could counter it, which resulted in the Pzkw V, known as the Panther and the Pzkw VI, the Tiger.  During the design competition that resulted in the Panther, one other suggestion was the production of a direct German copy of the T-34. 

The T-34, equipped with hand bars welded to the hull, was the first tank designed to carry infantry into battle, which was a tactic that brought real changes to the battlefield, since the infantry could ambush enemy tanks that didn’t expect their presence.

 Following the Second World War, the T-34 was widely exported and saw action in nearly every war fought between 1945 and 1995, when it was used during the Bosnian civil war. T-34s can still be found in some armies in Africa, making it likely the most widely-used and longest-serving tank in history."

Few do a background history like Tom Cleaver and so I boldly swiped the above from his review!