This book investigates the nature and properties of roots, the core elements of word meaning. In particular, chapters examine the interaction of roots with syntactic structure, and the role of their semantic and morpho-phonological properties in that interaction. Issues addressed in the book include the semantics and phonology of roots in isolation and in context; the categorial specification of roots; and the role of phases in word formation. Internationally recognized scholars approach these topics from a variety of theoretical backgrounds, drawing on data from languages including German, Hebrew, and Modern Greek. The book will be of interest to linguistics students and researchers of all theoretical persuasions from graduate level upwards.