Since the turn of the century the phenomenon of learning has received increasingly more attention. Within the theoretical field, a variety of theories of learning have evolved. The field of research on learning has become very complex, with different foci, founders and proponents, schools, and disciplinary approaches. This book is a first publication in the ‘On the definition of learning’ network. The network arose out of the aspiration to study the phenomenon of learning in depth and to understand its complex relationship to empirical investigation and teaching. Based on the assumption that it is important to be sensitive to the variety of concepts and theories of learning in the field, and to continue to cultivate that variety, the book takes a step towards actively and critically engaging the various approaches in the field of learning theory. At the same time it emphasizes the complex relationships that exist between conceptualizations of learning and the empirical phenomenon of learning and teaching. It discusses how conceptualizations of learning are put to work in educational contexts and how the normative aspects of learning in relation to discussions of what is considered worth learning influence the formative processes of human development.