Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) comprise various conditions, which are caused by infection from the human immunodeficiency virus (HIV). This virus usually spreads through unprotected sexual activity, blood transfusions, hypodermic needles, and from mother to child. There is no danger of acquiring HIV from feces, nasal secretions, saliva, sputum, perspiration, tears, urine, or vomit uncontaminated with blood. When the virus is acquired, it replicates inside and destroys T helper cells, which are necessary for all adaptive immune responses. There is an initial period of influenza-like illness in this disease. The treatment of HIV infection is determined by the stage of the disease. The treatment aims to keep the immune system from deteriorating to the point where opportunistic infections are more likely. Patients with weak immune systems are also less prone to immune reconstitution syndrome. The primary treatment of HIV includes highly active antiretroviral therapy (HAART), which decreases the growth of the disease. This book explores all the important aspects of HIV and AIDS in the present day scenario. Also included herein is a detailed explanation of the various diagnostic and management techniques associated with this medical condition. The book is appropriate for students seeking detailed information on this disease as well as for experts.