The time is not far off when not only theologians and a large part of philosophers and natural scientists, but also many doctors thought teleologically: In all the processes they observed in humans during healthy and sick days, they asked themselves why these occur and what purpose they serve for the organism. This teleological view of even disease phenomena has always been deeply rooted in the public consciousness. The ancient notion that illness is a struggle of the body against an invading enemy, which ends in recovery or death depending on which side prevails, as well as the still widespread belief among laypeople that fever, inflammation, suppuration, sweating, coughing, and diarrhea serve to remove harmful and impure substances from the body, prove this. This book is about hyperemia.