Despite the lengthy existence of the concept of lifelong learning, there is still no one generally accepted theory of education as a lifelong process. More than an extension of adult education, lifelong learning rests on the belief that learning occurs throughout life, in different ways and through different processes. The key notion in lifelong education is that all individuals ought to have a variety of organized and systematic opportunities for instruction, study, and learning at anytime throughout their lives. There are four key elements of lifelong learning. These are (1) horizontal integration (the concept that in-school education should be coordinated with other components of society in which learning occurs); (2) vertical integration (the principle that education should be highly integrated and interactive with events at various age levels); (3) lifelong learners, who are conscious of themselves as learners throughout life; and (4) a lifelong learning curriculum. A system organized according to the principle of lifelong education would be a quinary one involving early, elementary, secondary, postsecondary, and adult education. Professional adult education associations have a definite role in advocating the concept of lifelong learning at the state, regional, and national levels. (MN)