The book brings together into a single text the interrelated but different research efforts to translate the current evidence on risk and outcome of severe mental disorders into a preventive perspective. The book also introduces a holistic approach to prevention in mental health, by combining biological, psychological and environmental evidence that attempts to blunt the risk and reduce the number of individuals with mental health vulnerabilities who eventually progress to the manifestation of a severe mental disorder. Finally, the book wants also to highlight the possibility to overcome the single disorder-oriented preventive approach in an attempt to intercept a wider at-risk youth population and explore clinical research areas underperformed where future efforts will have to concentrate. Mental health problems have their peak of incidence during the transition from childhood to young adulthood, interesting up to 20% adolescents. Half of those eventually developing such difficulties experience clinically relevant mental distress by the age of 14. Even more importantly, the symptomatic onset is generally anticipated by non-specific warning signs of psychosocial impairment potentially evolving in any severe mental disorder. This is of crucial importance, as almost one in two health problems contributing to the global disease burden across the 0-25 age span is a mental disorder. The search for preventive strategies among youth has developed over the past 2-3 decades, invigorated by a rethinking of mental disorders' ineluctable prodromal phase into a period where the trajectory of illness can be slowed down, blunted, or even halted. The paradigms for implementing preventing approaches in mental health have often developed independent of each other. This book aims at summarizing the available evidence and make a step towards a more mature vision of the potentialities of promotion and prevention in mental health.