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 machine with a 120-mm "pike nose" and a powerful cannon capable of penetrating more than 200 mm of armor exceeded all tanks of all likely opponents of the Soviet Army and remained in service for 40 years (the last "dozens" were withdrawn from service only in 1993). But at the same time, 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 did this tank show itself during Operation Danube to bring our troops into Czechoslovakia in 1968? How many of these cars were actually produced (the sources "walked" a variety of numbers - from 1400 to 8000)? And why did T-10 become the last heavy tank of the Soviet Union? Answering all these questions, the new book of the leading historian of armored vehicles for the first time restores the full history of the creation, production and forty-year service of Stalin's last "supertank."