Secret education (tajne komplety) –  the first secret sets were created in Polish lands during the Partitions, when the authorities eliminated Polish from schools – the intelligentsia organized underground education in the Polish language.

Secret education spread widely during the German occupation between 1939 and 1945. The German authorities eradicated Polish secondary and higher education, and in primary schools they prohibited teaching the history, literature and geography of Poland. As soon as 1939, teachers established the Secret Teaching organization, which worked on the coordination of organizing the “secret sets”. The lessons usually took place in few person groups, in private flats. In the school year of 1943/1944, 90,000 students took part in the sets organized by about 5,500 teachers. The education covered all levels, including higher education, for instance in Warsaw: University of Warsaw, Free Polish University, Medical University, School of Economics and Music Academy. The underground education was severely fought down by the German occupational authorities.