Solar ultraviolet (UV) radiation has influenced the evolution of life on earth and was one among the possible causes for the different skin pigmentation in humans: those inhabiting low latitudes, with high UV intensity, have darker skin pigmentation to protect from the deleterious effects of radiation, while those in higher latitudes have developed fair skin to maximize vitamin D production from much lower ambient UV. In the last centuries there have been an increase in human migration from original areas and changes in habits and attitudes, causing that human skin pigmentation is no longer necessarily suited to the environment. In addition, the documented stratospheric ozone downward trend in the 90s of the last century and its still slow recovery have been associated, at least theoretically, with an increase of solar UV at the earth’s surface. The purpose of this book is to suggest and test a methodology, based on polysulphone dosimetry, for the assessment of solar UV exposure and to search for possible biological indicators of its effects. An overview of the problem is offered and some field experiments performed with groups of volunteers are presented and discussed.