Any book under this title which creates both anticipation and anxiety must be the work of a lot of people, present any new findings with objectivity and cover the subject as exhaustively as possible. As such, it must cover the possible reproducible mechanisms of action/reaction EMF-Biological Organism, the appropriate models that allow quantitative measurements, the basic biological reproducible effects and possible therapeutic effects along with their prevalent metrics and international exposure criteria. This is exactly the main objective of this book. It is also believed that it provides some new results and conclusions which complement, clarify and verify the existing results in the literature included in the references [1] and [2]. Electromagnetic Radiation is a form of energy, which is transmitted in the form of waves which correspond to spatial and time variations of the electric and magnetic field. Electromagnetic fields appear in a vast set of frequencies (spectra) that are divided in frequency zones, according to the manner they are produced or used. Areas greater than 300 gigacycles (GHz), which include the solar spectrum, as well as x and gamma rays, have been studied sufficiently under a different angle in relation to possible biological effects. People are well aware of the harmful effects of sun radiation when they are exposed to the sunlight for extended periods of time and of the catastrophic effects of nuclear bombs and nuclear reactor leaks.