The existence of coherent excitations in active biological systems has been established in recent years. The present book aims at presenting a survey on the many features that such ex- citations can exhibit. This does not mean that a "theory of biology" has been established but it implies that such a theory will make use of such excitations. It is hoped that the present book will help in this direction. April 1988 H. Frohlich Contents Theoretical Physics and Biology H. Frohlich ...1 ...Theory of Non-linear Excitations F. Kaiser (With 9 Figures) ...25 Structures, Correlations and Electromagnetic Interactions in living Matter: Theory and Applications E. Del Giudice, S. Doglia, M. Milani and G. Vitiello...49 Resonant Cellular Effects of Low Intensity Microwaves W. Grundler, U. J entzsch, F. Keilmann and V. Putterlik (With 14 Figures) ...65 ...The Influence of Low Intensity Millimetre Waves on Biological Systems F. Kremer, L. Santo, A. Poglitsch, C. Koschnitzke, H. Behrens and L. Genzel (With 17 Figures) ...86 Metastable States of Biopolymers J. B. Hasted ...102 Physical Aspects of Plant Photosynthesis F. Drissler (With 25 Figures) ...114 Emission of Radiation by Active Cells J. K. Pollock and D. G. Pohl (With 6 Figures) ...140 Physiological Signalling Across Cell Membranes and Cooperative Influences of Extremely Low Frequency Electromagnetic Fields W. R. Adey (With 7 Figures) ...148 The Interaction of living Red Blood Cells S. Rowlands (With 2 Figures) ...171 The Genetic Code as Language F. Frohlich ...192 ...