There is no vaccine or cure available for HIV; hence it is a prominent global health threat. To beat the challenges of HIV/AIDS, one must have sufficient knowledge of HIV infection. This book discusses various forms of HIV-host interactions in vitro and in vivo, like the interrelation between cellular components and HIV proteins, Integrase, Tat, and Nef, as well as the clinical pertinence of HIV superinfection. The book also examines the function of innate immunity along with dendritic cells and defensins in HIV infections and the effects of host factors on HIV pathogenesis. Topics like co-infection are also included that talk about the influence of Human herpesvirus 6 and Trichomonas vaginalis on HIV infection. The book also includes a discussion on the generations of HIV molecular clones that can be applied in macaques and the potential usage of cotton rats for HIV studies.