Prions, probably the most fascinating proteins ever studied, have been in the spotlight for the last 30 years. However, their history is much older. Indeed, the symptoms of what are now known as prion diseases were first described in Europe in sheep in 1730 and called "scrapie" in England, "vertige" in France and "Traberkrankheit" in Germany. This book discusses the development of prions and their various diseases.