Understanding diversity should help break down barriers to effective treatment and research of substance dependence. In this textbook, the author defines what is meant by diversity and reviews what we know today about the effects of alcohol, tobacco, marijuana, cocaine and crack, hallucinogens and heroin. This is then put into a broader context by examining the development of policy with particular emphasis on those who were perceived to be the most fervent users of substance. Communities examined include: African Americans; Asian and Pacific Islanders; Hispanic / Latinos; women; and gay, lesbian, bisexual and transgender. The book concludes with guidelines for the integration of diversity considerations into treatment programmes for and research procedures within these communities. This should be a useful textbook for classes on substance abuse and should also help the seasoned clinician to break down barriers in the understanding and treatment of substance dependence within specific communities.