U.S. support for global health has been motivated in large part by concern about emergent and re-emerging infectious diseases. Following outbreaks of diseases like severe acute respiratory syndrome (SARS), HIV/AIDS, and pandemic influenza, several presidents have highlighted the threats they pose to economic development, stability, and security and launched a series of health initiatives to address them. In 1996, for example, President Bill Clinton issued a presidential decision directive that called infectious diseases a threat to domestic and international security and called for U.S. global health efforts to be co-ordinated with those aimed at counter-terrorism. President Clinton later requested $100 million for the Leadership and Investment in Fighting an Epidemic (LIFE) Initiative in 1999 to expand U.S. global HIV/AIDS efforts. President George W Bush recognised the impact of infectious diseases on domestic and global security in his 2002 and 2006 national security strategy papers and created a number of initiatives aimed at them, including the President's Emergency Plan for AIDS Relief (PEPFAR) in 2004, the President's Malaria Initiative (PMI) in 2005 and the Neglected Tropical Diseases (NTD) Program in 2006. President Barack Obama also recognised the risk of infectious diseases and made several statements about how their spread across developing countries might impact U.S. security. Through the 2010 Quadrennial Diplomacy and Development Review (QDDR) and the 2010 National Security Strategy, the Obama Administration advocated for the co-ordination of health programs in other areas, such as security, diplomacy and development. Rather than create an initiative aimed at infectious diseases, President Obama sought to address them by affirming U.S. commitment to global health and refining how U.S. global health programs function. In 2009, President Obama announced the Global Health Initiative (GHI), a $63 billion, six-year strategy aimed at improving the co-ordination and impact of U.S. global health initiatives. This book provides an overview of global health programs and their effectiveness.