When ADHD, depression, anxiety and conduct and learning disorders emerge in childhood, they increase the risk that a young person may later develop substance use problems. In addition, bipolar disorder and schizophrenia tend to appear during adolescence and young adulthood-about the same time that substance use problems tend to emerge.This extensive and important resource on youth and concurrent mental health and substance use disorders is a well-researched and practical tool for all professionals working with youth.The manual is divided into three main sections:• Part One includes an overview of youth substance use and mental health, along with chapters on preparing to respond; identifying, assessing and planning treatment; treatment and support; and pharmacotherapy.• Part Two is an informative appendix that includes information on risk factors and protective factors, a comparative overview of substance use and mental health services for youth in Ontario, a Do You Know... section with everything you need to know about numerous substances, brief summaries of screening and assessment tools, and information on psychiatric medications.• Part Three consists of First Contact: A Brief Treatment for Young Substance Users with Mental Health Problems, a treatment manual to help care providers integrate the treatment of substance use and concurrent mental health problems.