This first volume of the 90-90-90 Compendium is targeted at a wide range of readers in South  Africa, including community members and/ or politicians with no medical background. It is designed to assist all health sector role-players in understanding the context of the 90-90-90  strategy, as developed by the Joint United Nations Programme on HIV/AIDS (UNAIDS), and then the process for achieving the strategy's targets. With South Africa's adoption of the 90-90-90 strategy in December 2014, the country turned a corner in its approach to managing the dual epidemics of HIV and AIDS on the one hand and tuberculosis (TB) on the other. Together, the two epidemics form the leading cause of deaths in the country.