This book presents a detailed and updated review of the widespread changes that take place during adolescence, adopting a preventive perspective that reflects physical, social, cognitive, and emotional changes. It addresses a broad range of aspects, including: the preventive programs and their systemic effects; the role of environment in influencing the healthy behaviors of adolescents and young adults; the use of e-Health technology in health and behavioral interventions for adolescents; and the clinical and prognostic implications of primordial prevention in healthy adolescents. All of these elements are subsequently reviewed using a multidimensional approach, in order to offer extensive information on the complex changes that characterize adolescents’ physiological, psychological, and neurobiological development. In addition, the book depicts the preventive strategies currently used in various social settings (school, family, sport club, health policies) aimed not only at reducing lifestyle risk behaviors, but also at improving resilience, happiness, social involvement, self-esteem, and sociability. This update is essential in the light of the fact that, to date, prevention has mainly been directed towards adolescents with physical or mental disorders rather than their healthy peers. As such, the book offers a valuable tool for pediatricians, child and adolescents psychiatrists, and for all professionals involved in Health Promotion and Disease Prevention.