Peter Aggleton (PA) is Professor of Education and Health and holds a UNSW Strategic Chair at the National Centre in HIV Social Research, University of New South Wales, Australia. He is well known internationally for his analytic work on the social aspects of HIV, sexuality and sexual and reproductive health. He is the editor of the international peer reviewed journals: Culture, Health and Sexuality and Sex Education, and is Associate Editor of the journals AIDS Education and Prevention, Global Public Health and Health Education Research. He has global experience researching the social aspects of HIV-related prevention, treatment and care and has worked closely with a range of bilateral and UN system agencies to strengthen the international response to HIV. Purnima Mane (PM) is currently Chief Portfolio Director at the Global Fund for AIDS, Tuberculosis and Malaria in Geneva, where she is responsible for overseeing management of funding decisions in Africa, Asia, Eastern Europe and Latin America. Her work brings her into regular contact with researchers and practitioners active in the field of youth and international health. She is the author of the best-selling book AIDS in the Sociocultural Context of India (Mumbai, 2002), a Founding Editor of Culture, Health and Sexuality, and on the editorial board of several journals including Sex Education. Prior to her present post, she was Vice President of the Population Council in New York and Director of its International Programs Division. Before that, she held a senior post within the Joint United Nations Programme on HIV/AIDS (UNAIDS) in Geneva. In the year 2000, together with Peter Aggleton and Andrew Ball, she edited a special issue of the journal Sex and Relationship Therapy on the theme Communicating with Young People. This addressed sex and substance use concerns. Andrew Ball (AB) is currently the Responsible Officer for the Regions of Europe and the Eastern Mediterranean in the WHO Department of HIV/AIDS, covering 75 countries across western, central and eastern Europe, the Middle East, north Africa and south-west and central Asia. In this capacity he works closely with countries in supporting the development and implementation of national and regional HIV/AIDS programmes. He has worked in WHO for twelve years, initially in the Programme on Substance Abuse, then the Department of Child and Adolescent Health and Development, before moving to the Department of HIV/AIDS. His work has focused on the young people, substance use and HIV/AIDS. He was co-editor of the book Injection Drug Use and HIV/AIDS, has authored a number of chapters and papers on HIV/AIDS prevention among injecting drug users, HIV/AIDS and substance use assessment methods and substance use among street children. Together with Purnima Mane and Peter Aggleton, he edited a special issue of the journal Sex and Relationship Therapy in the year 2000 on the theme Communicating with Young People, which examined addressed sex and substance use issues and concerns.