This five-volume set brings together articles from internationally-renowned scholars, seeking to address the various questions that have arisen; the forms of analysis that have developed in the field; the accumulation of theoretical and empirical knowledge about IOR; the continuing debates; and to offer suggestions about the next generation of research. Overseen by an international team of editors who provide a map of the field through a new comprehensive introduction, this work will be of interest to scholars across a wide range of disciplines, and is structured to reflect both chronology in development of the topic, and the conceptual and empirical knowledge that has accumulated.