This tool has been prepared by FOCUS on Young Adults primarily for those who design and deliver programs and who formulate policies concerned with the well-being of young people in the developing world. It specifically explores (a) adolescence as a distinct stage in the developmental process,(b) the defining characteristics of adolescence, (c) the variety of factors that influence it, and (d) its societal and cultural relevance. In addition, the tool looks at the relationship between the developmental characteristics and the appropriate outreach and service delivery strategies designed to promote health and to reduce the life-altering hazards that are often initiated during this critical stage in the human life cycle. Further, the tool recognizes the strengths and promise of adolescence while seeking to help adolescents avoid negative outcomes from sexual activity and poor reproductive health care, including sexually transmitted infections and unintended pregnancy. This tool suggests some health and development strategies and interventions that are most effective under specific societal and cultural conditions. Others have universal applicability and value across societies, including the following: provide education and skill-building for in-school and out-of-school youth; provide factual reproductive health information; involve youth caretakers, including parents, extended family, or other adults such as teachers and youth workers; involve youth themselves in program design, development, implementation, and evaluation; ensure access to counseling and other services that respond to the special needs of adolescents; increase collaboration and effective referrals among existing health and other development agencies and organizations serving youth; reach out or go to youth where they congregate, rather than making them come to service providers; train program site managers, service providers, and others to improve their interactions with youth; have clear goals, target populations, and indicators while building in monitoring and evaluation from the beginning of a project; use such findings to improve strategies and services.Although this tool is not intended as a "blueprint," we hope it will help you understand adolescent developmental needs so that you can design more practical, effective programs. The design of the tool provides a quick and ready reference so that you can learn more about adolescent development. The pull-out sheet allows you to work with staff members, young adults, community members, and others in planning program strategies and in thinking creatively about how to adapt ongoing reproductive health programs or how to develop new programs to serve specific adolescent populations. We encourage you to test interventions with opinion leaders, parents, other important extended family members, youth caretakers, and, above all, adolescents themselves.