Adult education forms an important element of lifelong learning. While ‘lifelong learning’ is not strictly part of the right to education, it is a concept that represents the continuity of the learning and educational process, and this is reflected in the right to education by the fact that it begins at birth and continues throughout life.
The UNESCO Institute for Lifelong Learning (UIL) provides the following definition:
‘In essence, lifelong learning is founded in the integration of learning and living, covering learning activities for people of all ages (children, young people, adults and elderly, whether girls or boys, women or men), in all life-wide contexts (family, school, community, workplace and so on) and through a variety of modalities (formal, non-formal and informal) that together meet a wide range of learning needs and demands’ (UIL  Literacy & Basic Skills as a Foundation for Lifelong Learning).
For more information, see the UN Special Rapporteur on the right to education’s 2016 report on lifelong learning and Report of the International Commission on Education for the 21st Century (Delors Commission) to UNESCO (1996) Learning: The Treasure Within.