«Polonica»: definition, selection criteria, use in Polish bibliography

The article discusses problems related to the Polish retrospective national bibliography formation. A brief historical overview of the issue is presented based on the Polish bibliography main work - «Bibliografia Estreichera». The definition of Polonica functioning in the modern library practice in Polan is given, as well as guidelines of materials selection for the national bibliography. It shows the difficulties with existing principles of referring works to Polonica evidently for publications of XVI-XVIII centuries, while explaining its individual criteria such as territorial, national, thematic and language ones.