This volume has been prepared in light of the experiences of primary care physicians and other health care providers, taking into account their specific needs. Short, user-friendly and oriented towards management, the book contains essential information for both physicians and other primary care staff on how to help patients with mental disorders. The book provides helpful guidelines on diagnosis in cases where the primary care physician has to do this alone. It also provides guidelines on what to say to patients and their families, how to give them counselling, what medication to prescribe, and when to consult a specialist. In short, this volume presents the knowledge of mental health science in an easily understandable form for practitioners at the primary health care level. Two versions of the ICD-10 Chapter V Primary Care Version (ICD-10 PC) are presented in this book: (1) a concise version for those with medical training and prescription responsibility; (2) a brief version for primary care staff with other medical training. The primary care versions of the mental disorders classification were designed by an international group of general practitioners, family physicians, mental health workers, public health experts, social workers, psychiatrists and psychologists with a special interest in mental health problems in primary health care. Drafts were reviewed by both mental health and primary health care providers. After two rounds of revision, the classification system was field tested in more than 40 countries by over 500 primary care physicians to assess its relevance, ease of use and reliability. This volume is therefore a highly practical, simple-to-use tool which can help make mental health a more integral part of primary health care practice.