The monograph presents the changes in Poland's substantive criminal law system after the Second World War. The author focused primarily on the codification process, including the issues of jurisprudence and extra-code regulations that were issued in 1947-1969.

The work has been divided into four parts, corresponding to the successive stages of adopting the penal code by the Sejm of the People's Republic of Poland on April 19, 1969. The first part deals with issues introducing the codification of criminal law in a communist state. The next three include work on draft codes from 1956, 1963 and 1968. Each part is presented in the context of socio-political changes in the political system of People's Poland.

The effects that the author reached as a result of the research carried out include, among others, the features of the codification process in the years 1947-1969, the reasons for the design work and the characteristics of the penal code of the people's state.