In the United States, prevention has already averted more than 350,000 HIV infections. Now, we have the potential to go much further. The nation’s HIV prevention efforts are guided by a single, ambitious strategy for combating the epidemic: the National HIV/AIDS Strategy (NHAS). Recent scientific breakthroughs have equipped us with an unprecedented number of effective tools to prevent infection. And in many of the communities hardest hit by HIV, there is growing leadership and momentum for change.