This overview report summarizes the outcome of Phase One of the Drugs Misuse Research Initiative, which was funded through the Policy Research Programme at the Department of Health. The views expressed are those of the author and are not necessarily those of the Department of Health. The brief summaries of key messages and findings from each project are drawn from their final reports and executive summaries, and from commentaries on and discussions of these reports. The selection of what are "key" findings and lessons for research, policy, and practice are those of myself, as author of the overview report, but derive directly from the substantial reports produced by project teams. I hope I have done justice to their work, while recognizing that the interpretation and contextualization are my own, as is responsibility for any errors. The authors of the executive summaries which follow the overview report are the project teams themselves.