Autoimmunity refers to the immune responses of an organism against its healthy cells and tissues. Whenever a human body exhibits an abnormal immune response to a normal body part, the condition may be termed as an autoimmune disease. The immune response can be targeted at any body part. Some of its common symptoms are recurring tiredness and low-grade fever. While some autoimmune diseases are triggered by environmental factors or infections, some are genetic. Common examples of autoimmune diseases are alopecia areata, Graves' disease, celiac disease, inflammatory bowel disease, systemic lupus erythematosus, etc. The treatment of these generally includes management of the symptoms rather than absolute cure of the disease. This book provides comprehensive insights into autoimmunity and autoimmune diseases. It discusses the fundamentals as well as modern approaches in the treatment of these disorders. It will serve as a valuable source of reference for graduate and postgraduate students alike.