Self-help organizations across the world, such as Alcoholics Anonymous, Croix D'Or, The Links, Moderation Management, Narcotics Anonymous, and SMART Recovery, have attracted tens of millions of individuals seeking to address addiction problems with drugs or alcohol. This book provides an integrative, international review of research on these organizations, focusing in particular on the critical questions of how they affect individual members and whether self-help groups and formal health care systems can work together to combat substance abuse. Keith Humphreys reviews over 500 studies into the efficacy of self-help groups as an alternative and voluntary form of treatment. In addition to offering a critical review of the international body of research in this area, he provides practical strategies for how individual clinicians and treatment systems can interact with self-help organizations in a way that improves outcomes for patients and for communities as a whole.