This article is devoted to the problems of the "relapse of Pokrovshchina" - a phenomenon in the history of historical science, which was characterized by the dominance of sociologized schemes, the leveling of the role of source analysis, the lack of developments in problem areas of auxiliary historical disciplines, the primacy of modern studies to the detriment of the study of classical history. The famous Soviet Byzantine historian Mikhail Jakovlevich Sjuzjumov (1893-1982) resolutely opposed the crisis of this "growth disease". In his personal fund (GASO, F. P-802) contains letters to leading experts in various branches of historical science, where he analyzes in detail the essence of the "second edition of the Pokrovshchina" (the second half of the 1960s). Two letters of M. Ja. Sjuzjumov are introduced into scientific circulation. One of them, dated by the author on May 5, 1965, is a response to the appeal of the editor-in-chief of the magazine "Questions of History" to Vladimir Grigoryevich Trukhanovsky (1914-2000) and a letter dated July 2, 1965 to the Soviet statesman, First Secretary of the Komsomol Central Committee Sergei Pavlovich Pavlov (1929-1993). In fact, they are journalistic articles, a reflection on the results of the All-Union Meeting on measures to improve the training of scientific and pedagogical personnel in historical sciences, convened by the decision of the Central Committee of the CPSU and the SNK of the USSR. M. Ja. Sjuzjumov considers the popularization of historical knowledge to be a recipe for the destructive action of the Pokrovshchina.