Croatian historian Prof. Dr. Ivan Očak (1920—1994) graduated from the History Faculty at Moscow University "Lomonosov". He also took his doctor's degree there and lectured "history of Yugoslavia" for twenty years. After his return to Zagreb in the seventies, he was active as a scientific councillor at the Institute for Croatian History at the Faculty of Arts, Zagreb University- His scientific-research work was focused mostly on researching the Yugoslav workers' and communist movement between the Wars, as well as on Stalin's purges among Yugoslav (communist) emigrants in the Soviet Union. His opus consists of over two hundred scientific works (among them twenty books), published both at home and abroad.