The study of metal hydrides opens up promising avenues for the solution of world energy problems, as well as casting light on the interactions of hydrogen with materials, the role of hydrogen in materials science, and the chemistry of metal hydrides, all of which are discussed in this book in terms that range from a global look at the new vision of energy and how hydrogen fits into that future to reviews such as a look at nickel hydride over the last 40 years. Very specific current research in such areas as hydrogen in materials science discuss properties like superconductivity, diffusion EMF, magnetic properties, physicochemical properties, phase composition, and permeability. Hydrogen can also be used as a processing or alloying agent, and in the synthesis of battery electrodes, composite materials and alloys. The interaction of hydrogen with many metals, composites and alloys offers potential hydrogen storage systems. There is also a discussion of hydrogen sensors.