The Concerned Other is a major new theoretical work with extensive research - documented in over 150 references - that demonstrates why and how families can influence the change in problematic drug and alcohol abuse by a family member. Author Phil Harris sees 'the concerned other' as the person most able to effect change in the abuser's life, while also taking proper care of themselves. The book presents the thoroughly researched and carefully argued theoretical underpinning of Harris's work with substance users and their families. It will be essential reading for academics, researchers, students, policy-makers, and those people working with alcohol or substance abuse, who want to bring themselves up-to-date on current ways of thinking, but who do not need the full intervention-based worksheet program that has been available in Harris's complete manual (The Concerned Other - ISBN 978 1 905541 48 5 - Paper - $99.95 - 304pp - 2010). The entire theoretical text of this present book was previously published as Part 1 of the complete treatment manual. Here, it has been published separately from the worksheet program, in response to demand from both students and practitioners who wish to focus on the theory and who want to study the work with concerned others, rather than undertake it.