The fact that electromagnetic radiation has positive as well as negative effects was known already in ancient times. However, the science of photobiology started to develop only more recently [1]. It was at the beginning of the twentieth century when vigilance against signicant sun exposure (a relic of the nineteenthcentury) started to erode and the roots of later attitudes toward sunbathing were already manifested. The rst clinical observations associating long-term sun exposure not only with benecial effects (phototherapy) but also with skin cancer were also reported during this time [2].