The book, by comparing documents from Soviet and German military archives, shows the actual course of hostilities on the days of the defensive operation. The above facts indicate that the counterattack on July 12 near Prokhorovka, contrary to widespread belief, ended in a major failure, which complicated the further actions of the troops of the Voronezh Front. The reasons for the failure and large losses of our troops, which significantly exceed the official data, are revealed. Nevertheless, the front troops, having successfully completed the defensive operation, created the conditions for the transition of our troops to a decisive counterattack and the defeat of the Belgorod-Kharkov enemy group.