The Food and Drug Administration (FDA) approved and licensed a drug to prevent HIV acquisition in 2012. This is the first ever FDA drug approval for HIV prevention. Tenofovir combined with emtricitabine (Truvada (R)) was licensed to be used in conjunction with other HIV prevention methods by HIV negative people at high risk of HIV acquisition. This novel method of HIV prevention is termed HIV pre - exposure prophylaxis (PrEP). Whilst the use of PrEP has been implemented in some countries, this is still a new method and several countries are to still implement PrEP. The use of PrEP will go a long way in globally controlling the ever surging rise of the AIDS epidemic. This book, therefore provides an extensive description of PrEP from basic information to scientific studies. It offers a concise and comprehensive description of how Truvada (R) was tested for safety and efficacy in both animals and humans. In addition, it describes the safety profile of Truvada (R) for PrEP. This book is especially useful to clinicians, medical personnel, pharmacists, regulatory authorities and even consumers who may require more information on this novel and effective drug to prevent HIV.