This is the first monograph entirely devoted to the IS-4 heavy tank. Developed as a response to the appearance of German heavy tanks and self-propelled guns in the summer of 1943, the tank, designated “object 701,” turned out to be a vehicle with a difficult fate. Created almost from scratch, the tank could not keep up with rapidly changing requirements and was already outdated when it was put into production. These vehicles had low transmission reliability, low cross-country ability and maneuverability, and in terms of artillery armament they had no advantages over the IS-2 and IS-3. The book describes the history of the IS-4 in as much detail as possible, from development to operation in the army. Many materials used in the book are being published for the first time.