This is a UNESCO publication for the furtherance of knowledge about atomic energy and its place in ordinary, peaceful living. A guidebook, translating the language of science into simpler terms, it defines and explains energy, the nuclear fuels and their sources, the methods of extraction and separation and the preliminary state of power in the reactors and atomic furnaces; then it goes on to power itself, radioactivity and the uses in industry, agriculture, in biological research, and the prospects of this new form as a social constructive and beneficent force within international cooperation. These chapters will be of help to schools and students, to the layman desiring an understandable explanation of this era's great development.