Preventing and treating chronic diseases is a major global challenge for health care this century. Motivating patients to improve their health behavior is essential to the long-term success of most interventions in this context. In the past 25 years, the Transtheoretical Model of Behavior Change, developed by Prochaska, DiClemente, Velicer and others, has contributed considerably to our understanding of how individuals change their health behavior. Current results of international work using the Transtheoretical Model were presented by many of the leading experts in this field at a meeting "Research on the Transtheoretical Model: Where are we now, where are we going?" in Marburg, Germany in August 2004. This book presents the extended abstracts of all meeting contributions. This one-of-a-kind collection provides an overview of current research on model development as well as on intervention evaluation. Additionally, the book includes addresses from several of the major researchers in this area. The editors hope that this book will stimulate further research and facilitate international networking and collaborations.