The fundamental system as the scientific basis of biological medicine. Where do diseases originate in the body, and where is therapy most effective? The answer is quite simple: in the fundamental system. The system of basic regulation is the scientific foundation of biological medicine, in which all biological processes are regulated. A disturbance in basic regulation is of fundamental importance in the development of diseases, particularly chronic conditions or tumors. The fundamental system also forms the common theoretical and functional basis for a variety of complementary medical methods. This textbook is a well-structured, detailed introduction to this complex explanatory model. It describes the regulatory relationships of the fundamental system, provides guidance for therapy, and establishes connections to individual therapeutic procedures. The 4th edition has been completely revised.