Textbook in PDF format The original text of this volume is that of the first four chapters of the book "Problems and Solutions in Thermodynamics and Statistical Mechanics" itself one of the "University Series" published by the Shokabo Publishing Company. Although the last part of the original book was translated first and published as "Statistical Mechanics. An Advanced Course with Problems and Solutions" (North-Holland Publ. Co., 1965), the present volume should be regarded as the first volume of the whole work. This is not the usual type of textbook, but it is aimed primarily to help the student to study the subject by thinking for himself and by working problems by himself. The solutions of the problems, of course, can be used in various ways. The lectures, entitled the fundamental topics, are therefore meant to be as concise as possible to make it convenient for the reader to refer to them repeatedly. Much of the material usually treated in textbooks is included sometimes in disguised form, in the examples or problems. In this respect this book is selfcontained. However, it may be recommended students to use a standard textbook together with the present book. Thermodynamic state and the first law of thermodynamics The second law of thermodynamics and entropy Thermodynamic functions and equilibrium conditions Phase equilibrium and chemical equilibrium Divertissements