This book examines the potential outputs of the various forms of energies in the world. These energy sourcesdirect fuel, coal, oil, solar heat, water power, wind power, or combustible materials from different sources are continually available. They may be contrasted with energy from fossil fuels, which, one burned, are not again available for human use. The data of all countries is appended in this book to make it more comprehensive the book has been taken from various sources viz. magazines, journals and books. Each is appraised with respect to its present technical status, its availability, usage and its stage of commercialization. The technologies are grouped according to their suitabilities to supply electricity, liquid fuels, or heat, since these forms of energy are closely related to each other.