This article is devoted to the methodology of research in the field of religiosity in the USSR. The author outlines the weaknesses of current scholarship: the lack of knowledge of others’ works, inability to widen the scope of used sources for a more multidimentional analysis, etc. He specifically refers to a problem of a researcher’s being concentrated exclusively on the documents from one particular “favourite” archival fund — usually “the fund of the commissioner for religious affairs” — which turns the research into an uncritical retelling of the documents found there.