"A mind without books is like a bird without wings"

The experience of describing the corpus of cyrillic printed books of the 16–18th, belonging to three regions, allowed to introduce several thousand sources into scientific circulation and raise fundamental issues of classification and further study of book culture. Several thousand sources were introduced into scientific circulation, which allowed for the first time to raise or solve fundamental issues of book culture, traditionally defining not only spiritual, but also and the state life of Russia.The article offers an excursion into the history of the study of the distribution of cyrillic old printed books in the 16–18th and the methodology of their description developed by the staff of the Archeographic Laboratory of the Lomonosov Moscow State University. The purpose of this study is to disseminate the positive experience gained from the theoretical and practical application of the methodology for further work on cataloging and describing cyrillic printed books in other regions of the Russian Federation.