This widely acclaimed text, now in its sixth edition and translated into many languages, continues to present a clear, simple and concise introduction to chemical thermodynamics. An examination of equilibrium in the everyday world of mechanical objects provides a starting point for an accessible account of the factors that determine equilibrium in chemical systems. This straightforward approach leads students to a thorough understanding of the basic principles of thermodynamics, which are then applied to a wide range of physical chemical systems. The book also discusses the problems of non-ideal solutions and the concept of activity, and provides an introduction to the molecular basis of thermodynamics. Over six editions, the views of teachers of the subject and their students have been incorporated. Reference to the phase rule has been included in this edition and the notation has been revised to conform to current IUPAC recommendations. Students taking courses in thermodynamics will continue to find this popular book an excellent introductory text.