This volume is based on the lectures and selected posters on different aspects of biological effects of EMF, presented at the NATO Advanced Research Workshop "The mechanisms of biological effect of Extremely High Power Pulses (EHPP)" and the UNESCO/WHO/IUPAB Seminar "Molecular and Cellular Mechanisms of Biological Effects of EMF" that took place in March 2005 in Yerevan, Armenia. The authors’ list represents the research centres from 21 countries from Europe, North and South America, Asia. The experimental data and theoretical models of EMF effect on various levels, starting from cell aqua bathing medium to the whole organism, including the human, applying multidisciplinary approaches. Both the beneficial use of EMF for diagnostics and therapy and the potential hazard of EMF in selected occupational and living conditions were discussed. The WHO project of harmonization of standards reflects in several papers. The emphasis is on the search for cellular and molecular mechanisms of the biological effect of EMF with different frequencies and field strengths. A novel approach to studying the non-thermal mechanisms of interactions of EMF and Extreme High Power Pulses, could serve as a valuable source of information for modern concepts in non-thermal effect of EMF. The Workshop presentations and papers included in this book covered a variety of topics such as theory of biological effect of extreme high power pulses; microwave induced pathologies (cancer, nervous and cardiovascular disorders); diagnostics and therapy with EMF; experimental evidence for biological effect of EHPP and would be helpful for designing research and policy standards, for search of mechanisms of interaction of EMF with living systems, for new advances in diagnostics and therapy.