This volume presents new work by leading researchers on central themes in the study of event structure: the nature and representation of telicity, change, and the notion of state. The book advances our understanding of these aspects of event structure by combining foundational semantic research with a series of case studies from a variety of languages. The book begins with an overview of the theoretical issues central to the volume, along with a brief presentation of the remaining chapters and the points of contact between them. The chapters, developed within several different theoretical perspectives, promote cross-theory as well as cross-linguistic comparison. The work will interest scholars and advanced students of morphology, syntax, semantics, and their interfaces. It will also appeal to researchers in philosophy, psycholinguistics, and language acquisition who are interested in the notions of telicity, change, and stativity.