The phenomenon of cannabis dependence has been a topic of interest and varying levels of concern for well over 100 years. As Roffman and colleagues recount in the first chapter of this book, our conceptions and understanding of it have been shaped by many social and political forces over time, but it is only in the last 20–25 years that science has directly been brought to bear on its nature, consequences, and treatment. It is this concentrated growth in knowledge that serves as the impetus for this book. We would be naive to believe that social and political forces no longer affect the current cannabis Zeitgeist. Yet the research reviewed in this volume offers a starting point for a rational consensus regarding a condition that some still argue does not exist and others would say is a major problem plaguing our societies. In this chapter we attempt some integration of the research findings, reach some tentative conclusions, and revisit directions for future research. Although the book is organized into sections that loosely correspond to what we know about the nature, consequences, and treatment of cannabis dependence, there is great potential for cross-fertilization of ideas across these different research areas and levels of analysis. Its nature and consequences ought to shape its treatment and results from treatment trials tell us something more about its nature. Hopefully, research in all areas will inform policy in a logical fashion.