The aim of the article is to present selected themes that form part of the contemporary discourse on informal learning, which since the 1970s has dominated the scientific debate on learning, especially in the area of adult education. The authors, using Polish and German-language literature, outline areas of scientific and research interest, as well as tendencies in the contemporary approach to the learning processes of adolescents and adults. Moreover, they present exemplary results of research on informal learning, conducted within various fields: adult education, social pedagogy, economics and others. They indicate that separate treatment of human learning (division into formal, non-formal, and informal learning) is not always justified, and is not conducive to the analysis of learning processes.