Thermodynamic methods of analysis have in recent years found ever-growing extensions in diverse regions of modern tech­ nology. The object of the present book is to apply these methods to the description of materials of varying physical properties. I hope the book will illustrate the wide variety and usefulness of thermodynamics which was well described by Albert Einstein: "A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon me." The work of the American thermodynamic school is well known in the Soviet Union, and thus it is a great pleasure to offer this book to American readers. V. V. Sychev v Preface At the present time, when a number of new areas of tech­ nology are rapidly evolving, it is difficult to present a modern course in technical thermodynamics without developing such sub­ jects as the thermodynamics of insulators, magnets, and super­ conductors, or without treating the features of thermodynamic systems located in a gravitational field and in conditions of weight­ lessness, etc. In fact the limited coverage of technical thermody­ namics in the usual textbooks and school equipment as a rule prevents the authors from giving any detailed discussion of these important problems. I therefore resolved to treat these problems in a separate text. I discussed the concept of this book with my teachers V. A.