In this chapter, the author explains the basis of the learning theory, i.e. the areas of knowledge and understanding which must underlie the development of a comprehensive and coherent theory construction. These include all the psychological, biological and social conditions which are involved in any learning. Under this is the central box depicting learning itself, including its processes and dimensions, different learning types and learning barriers, which are the central elements of the understanding of learning. Further there are the specific internal and external conditions which are not only influencing but also directly involved in learning. And finally, the possible applications of learning are also involved. The general conclusion is that learning is a very complicated matter, and analyses, programmes and discussions of learning must consider the whole field if they are to be adequate and reliable.