With the conclusion of adolescence, a child develops into a teenager that may experiment with dating, smoking and drinking, and they may make important decisions without parental knowledge or guidance. These teenagers may also engage in risky behaviour, which may pose as a threat to their well-being and successful transition into adulthood. With this in mind, how can we can prevent adolescent risk behaviour? Traditionally, prevention scientists propose three forms of prevention. Primarily, attempts to reduce the harmful consequences of risk behaviour, such as treatment of risk behaviour (ie: mental disorders or substance abuse) are ideal. For some problematic behaviour which has already occurred, a better approach is to identify those who are at-risk as early as possible (ie: secondary prevention). For example, youth workers may identify those who have suicidal ideation and intervene as early as possible so that they will not harm themselves. In this book, the authors assess whether a community-based program in Hong Kong was effective in promoting adolescent development and explore what factors were associated with the program effects. The authors hope that the studies included in this book can help to reveal the successful experience of the project and provide some pointers for the development of programs for adolescents with greater psychosocial needs.