This heavy tank was put into service six months after the death of I.V. Stalin, so the usual abbreviation “IS” was changed to T-10. This 50-ton vehicle with a 120-mm “pike nose” and a powerful cannon capable of penetrating more than 200 mm of armor surpassed all tanks of all potential opponents of the Soviet Army and remained in service for 40 years (the last “tens” were withdrawn from service only in 1993 year). But at the same time, the T-10M is perhaps the least known of the domestic tanks, since it was not exported and was strictly classified in the USSR (even the manual for its operation had a stamp). How this tank showed itself during Operation Danube on the entry of our troops into Czechoslovakia in 1968? How many of these machines were actually produced (there were a variety of figures in the sources - from 1400 to 8000)? And why did the T-10 become the last heavy tank of the Soviet Union? Answering all these questions, a new book by a leading armor historian restores for the first time the complete history of the creation, production and forty years of service of Stalin's last “super tank.”