This book explores serious diseases and disorders that most readers have never heard of, ranging from genetic, infectious, and environmental diseases to autoimmune, idiopathic, and mental disorders. Despite centuries of scientific study and medical research, there are still many human diseases and disorders that remain difficult to manage or are incurable. Some of these maladies are extremely rare, yet, together, they affect a substantial number of people. The 101 Most Unusual Diseases and Disorders examines seldom-seen illnesses, providing high school and college students with an excellent resource for research as well as supplying fascinating reading for general readers interested in diseases and medical science. This book provides clear, easy-to-understand, and scientifically grounded information on the vast number of unusual medical conditions that have been recorded, covering five kinds of diseases and disorders: genetic, infectious, environmental, mental, and "other," which constitutes diseases of autoimmune and unknown origin. Examples of the medical conditions addressed include autoimmune encephalitis, Ebola, kleptomania, Morgellons syndrome, orthorexia, pneumoconiosis, and Prader-Willi syndrome. Selected case studies enable readers to better empathize with the experiences of those who have these disorders and how these afflictions have affected their lives.