In recent years, considerable progress has been made in the study of organic semiconductors. The main directions of investigation, have been determined and substantial results have been achieved in the theoretical treatment of many questions. However, the range of investigations is so broad that it is impossible to discuss all branches fully in a short monograph. In fact, the chemist synthe- sizing systems with conjugated bonds and studying their reactivity, the physical chemist studying the catalytic and absorption proper- ties of substances with conjugated bonds, the physicist studying the...