The present volume describes the general properties of the thorium atom and ions, the thermodynamics of its compounds and solutions, the behavior of solutions and solid com pounds under the influence of its own radiation as well as an external radiation field, and spectroscopic data in great detail. The different chapters are of special interest to scientists who work in these fields, and also in the corresponding fields of other elements. In some special fields there exists a detailed knowledge of this radioelement whereas in other fields, such as M6Bbauer spectra, lower oxidation states, or...