Viktor Yakunin (1939-2017) is a well-known Ukrainian historian, Professor, head of the Department of Ukrainian history and Ethnopolitics of the Dnipro national University named after O. Gonchar. The basic ethical norms and scientific principles that guided the scientist in life and scientific work are defined. It is primarily the adherence to principles, courage and integrity. The most shameful act of both man and scientist, he considered betrayal. He was contemptuous of historians who adjusted to the political situation, who renounced what they had previously passionately preached. The most shameful act of both man and scientist, he considered betrayal. He was contemptuous of historians who adjusted to the political situation, who renounced what they had previously passionately preached. He is not an armchair scientist. He had a fighting character, took a firm civil position, was always politically active person, which was reflected in his scientific works, of which he wrote more than 150, including 5 monographs and 5 manuals. In them, the scientist studied the actual problems of historiography, methodology of history and political history of the USSR and Ukraine. In particular, he attempted to answer the question why the CPSU lost power and the USSR collapsed. In a number of his works, the concept of patriotism, which is opposed to nationalism, is revealed on concrete examples, a sharp but justified criticism of Ukrainian nationalism is given, the connection of the latter with Nazi ideology is shown. It is felt that he loved his lost Homeland immensely. He believed that it is impossible only to blame the Soviet past, not to see the achievements of Ukraine in this period.