While the development of atomic power holds great promise for the future as a replacement for fossil fuels that are rapidly being depleted, the underdeveloped countries have a particularly vital and immediate interest in devising low-cost sources of energy.  Mr. Daniels has spent many years studying the possibilities of converting the sun's rays into mechanical and electrical power, and in this volume he covers all aspects of the subject of solar energy.  Without stressing mathematical and engineering details (though including complete references to the sources of this kind of information), he describes the full range of the experimental work involving collectors of solar radiation, cooking and heating water, agricultural and industrial drying, storage of heat, solar furnaces and engines, cooking and refrigeration, and photochemical conversion.