A revival of interest in morphology has occurred during recent years. The Yearbook of Morphology series, published since 1988, has proven to be an eminent support for this upswing of morphological research, since it contains articles on topics which are central in the current theoretical debates which are frequently referred to. The Yearbook of Morphology 1999 focuses on diachronic morphology, and shows, in a number of articles by renowned specialists, how complicated morphological systems develop in the course of time. In addition, this volume deals with a number of hotly debated issues in theoretical morphology: its interaction with phonology (including Optimality Theory), the relation between inflection