This book reinvestigates and analyses, in various aspects and details, the scientific basis of an up-to-date 'nuclear culture' and presents the basic and outstanding problems of this field, with its important technical and social applications and consequences. The contributions are presented by leading experts in this area and the fundamental approaches related to nuclear fission and fusion have been considered and covered. In the light of public opinion regarding nuclear energy as a whole, after the Chernobyl accident, the various items, including safety and ecological problems, are treated beyond the political and social misunderstandings due to ideological and fashionable interferences. The resulting collection of papers therefore satisfy the double need of maintaining a high scientific standard and of presenting the data and the facts in such a way that they can be understood, in their essential aspects, by a more general audience.