The role gender relations play in the spread of the virus has gained increasing recognition. For example, women worldwide are less likely than men to be able to control whether, when and how sex takes place. It is also becoming clearer that women cannot change prevailing gender relations without the support of their male partners. Thus, engaging men is a critical component in HIV/AIDS prevention. This document helps those working with men, specifically in the field of HIV prevention, as well as more broadly in the areas of improved sexual and reproductive health. It examines 12 diverse projects, including Project Papai, which works with young men in Recife, Brazil to promote participation in health, education and child-rearing. It is believed that an analysis of their strategies and lessons learned would generate common ground on men's needs in association with HIV/AIDS and their general health, and would provide insights into effective approaches for working with men.