This booklet looks at all forms of teacher learning, formal and informal, from teachers. own early schooling, through their pre-service preparation and induction, and on to the end of their teaching career. It argues that to formulate policy and design effective programmes for teacher preparation and professional development, the whole spectrum of teacher learning must be considered. Much recent research and fresh knowledge have been brought together for the first time in this booklet. This includes literature on the nature of teacher preparation and professional development in developing countries (notably ambitious, innovative reforms), the rapidly growing body of research on teacher education and teacher learning in industrialized countries, the recently published analyses of the exceptional forms of professional development that exist in Japan and China, and the various positions taken by critics and proponents of teacher preparation and professional development as they exist today.