The present science book "Application of Solar Energy" is edited by Professor R. D. Rugescu in the series on Solar Power and consists of 7 chapters that begin with the proof of the high thermal efficiency of the gravitational draught through concentrated solar heating. It continues with novel technologies of producing organic fuels through solar heating, new types of photovoltaic cells, long term use of thermal solar power plants, the efficiency of thermal storage and applications in Niger of the Solar power. The reader will be pleasantly impressed by the accompanying drawings and pictures that ease the text assimilation and makes it an attractive practice.