Applications of heat have attractive potentials in oncology. Serious assessment is sometimes difficult, because thermotherapy or hyperthermia emerge today in various forms and labels such as nanotherapy, radiofrequency hyperthermia, annular phased array system, MR thermo-graphy, capacitive heating, whole body hyperthermia etc. The book provides an overview on the current status of thermotherapy and directions of further research and is directed to newcomers, but contains as well valuable hints and suggestions for specialists. A central concern is to identify promising indications for hyperthermia based on clinical studies and embedded into actual oncological guidelines. Another focus is a detailed description of heating technology in order to convey an idea whether or not a target is heatable and how to apply available devices at best. The author of this book is a renowned protagonist in this field and provides an essence useful for physicians as well as physicists, engineers and other scientists interested in the field of thermotherapy.