The authors show it is possible to create relationships between adults and young people that advance youth development and deter his or her detrimental behavior. In addition, the authors demonstrate these relationships can be fostered with a high degree of success, in widely varying localities, without the presence of charisma or other special factors. Mentoring's potential for intimacy between previous strangers creates the possibility for both risks and benefits that many other complex interventions do not contain. Mentoring works best within a supportive structure and when adult mentors behave in certain ways. Supportive structures and behaviors that produce effective mentoring are identified, and summaries of 10 mentoring reports are provided. 117 references