This book presents a comprehensive summary of the knowledge base around mental health issues in rural and frontier America. Challenges facing rural areas in meeting the needs of its citizens with mental illnesses and substance use disorders are highlighted. The book also reports on opportunities captured and unique solutions available. It briefly describes the methodology and selected findings of three large federally funded surveys that provide national prevalence estimates of diagnosable mental illness: the National Comorbidity Survey Replication (NCS-R), the National Comorbidity Survey Replication Adolescent Supplement (NCS-A), and the National Survey on Drug Use and Health (NSDUH). The book presents prevalence estimates of any mental illness and serious mental illness based on each survey and ends with a brief discussion of how these prevalence estimates might inform policy discussions.