Contents: I. Mathematical Preliminaries: 1. A Synopsis of Classical Thermodynamics. 2. Single component Fluid – Fundamentals. 3. Single Component Fluid – Applications. 4. Homogeneous (Single Phase) Mixtures. 5. Heterogeneous (Multiphase) Mixtures. 6. Reaction Equilibrium. The book presents the concepts and equations of equilibrium thermodynamics or thermostatics in a logical and compact manner. Key features that distinguish this book from others on chemical engineering thermodynamics are: a mathematical treatment of the developments leading to the discovery of the internal energy and entropy; a clear distinction between the classical thermodynamics of Carnot, Clausius and Kelvin and the thermostatics of Gibbs; an intensive/specific variable formalism from which the extensive variable formalism is obtained as a special case; a systematic method of obtaining the central equations of thermostatics with the use of the implicit/inverse function theorems and the chain rule.