This new resource from the DFID- and WHO- supported Safe Passages to Adulthood programme shows how projects in Africa, Latin America, South East Asia and the Middle East are working with young people in contexts of special vulnerability to prevent HIV. Building on the five core principles and three areas of action outlined in A Framework for Action - HIV/AIDS prevention and care among especially vulnerable young people (April 2004), each case study describes an innovative approach to working with young people who are homeless, using drugs, selling sex or living in deprived communities. Case studies come from Argentina, India, Iran, Kenya and Nigeria.