The book examines the theoretical and methodological foundations of non-formal education and its role in lifelong learning and adult education. The first chapter discusses the changes in education at the turn of the century, the differences between formal, informal and non-formal education, as well as the essence and attributes of non-formal education and forms of its realization. Chapter two explores the concepts of continuing education and adult education and their relationship with non-formal education. Conclusions by chapters summarize the results, and the list of used literature includes sources used in writing the book.