First published in 1966, this account of thermodynamics was written primarily for theoretical physicists and for experimental physicists and physical chemists wishing to enter more deeply into the fundamental principles of the subject. Although it starts at the beginning of thermodynamics and covers elementary and advanced topics, the elementary ideas are treated from an advanced standpoint. The first four chapters deal with both the classical and the axiomatic development of thermodynamics, and the discussion of the first and second laws is elaborated in such a way as to provide a rational basis for the derivation of the fundamental principles of statistical mechanics in Chapter 5. The remaining nine chapters of the book consist of applications of thermodynamics and of statistical mechanics, either separately or combined, to a wide variety of problems. A special chapter is devoted to the third law of thermodynamics.