Book excerpt: Adolescents undergo rapid physical, psychological and social developmental changes that result in management challenges, communication issues, patterns of disease and symptom presentations that are different from children or adults. This can be challenging for health professionals, who rarely have had specific training in dealing with the young people they meet in their clinical work. This ABC covers topics surrounding adolescent development, sexual behaviour and substance misuse, along with education and preventative strategies. It also features other adolescent health problems such as self-harm, eating disorders and psychosomatic presentations. This book is a valuable resource for all those who deal with adolescent patients in primary care, emergency departments, and hospital and outpatient settings.