This study of ceramics involves the ethnographic materials. In 1959-1962, A.A. Bobrinskiy, one of the leading domestic experts in ancient pottery, conducted a questionnaire survey of the population to identify the working pottery-production centers in the European part of the RSFSR, partly in the Ukraine and Belarus. In total, more than 6 thousand letters were sent with the attached questionnaire containing questions regarding the most important details of pottery production. The survey materials are the letters (handwritten, less often typewritten, sometimes accompanied by drawings) from local authorities, teachers, employees of local history museums, potters who answered the questionnaire with varying degrees of detail. Ca. 1000 (mainly rural) centers of pottery production were identified and characterized. These documents are stored in the Scientific Industry-Specific Archive of the Institute of Archeology of the Russian Academy of Sciences (A.A. Bobrinskiy’s personal archive) and only partially introduced into the scholarly discourse. They contain specific information on all stages of pottery production: selection, mining, preparation of raw materials and compositions of molding masses, constructing utensils and surface treatment, baking; as well as tools (including pottery wheel designs), heat engineering devices (furnaces and kilns), categories of pottery, vocabulary of potters, their customs and beliefs, trade relations within microregions and wider territories, etc. This valuable source characterizes the development of pottery production in the first half of the 20th century and contains specific ethnographic data, which are also important for the study of technology employed for the production of archaeological pottery finds. These unique documents can excite the interest not only of archaeologists and ethnographers, but also linguists and folklorists. “Potters’ Letters” can also be regarded as a source for studying the conditions of the rural population in the USSR in this period.