PZL P.11 was a basic type of fighter for Polish aviation equipment during the German invasion in September 1939. The aircraft was designed in 1931 by Eng. Zygmunt Pulawski. The publication includes the history of origins and development of fighter design from P.1 to P.24. A detailed technical description P.11a and P.11c. The author also presents shortly the course of battles in defence of the Polish airspace in September 1939. The book contains numerous photographs, drawings of aircraft projects, and colourful boards with camouflage and markings.