In this volume (volume 1), the fundamental aspects of thermodynamics are presented. The first & second laws of thermodynamics are illustrated. The need to define thermodynamic temperature & the nature of entropy are explained. The book explores the meaning of auxiliary thermodynamic functions, the origin, usefulness & use of partial molar quantities. Gaseous systems & phase equilibrium, in systems where chemical reactions do not take place, are described In volume 2, the tools necessary to study & understand systems in which chemical reactions can take place are developed. The variables of reaction are the keys to understanding. Criteria for chemical equilibrium are established. It is shown how chemical reactions can provide work, as for example, in batteries. For complex systems, the number of independent reactions & their nature have to be determined systematically. The effect of external factors on chemical equilibria is analyzed & illustrated. The formalism necessary to study ideal & real solutions is provided. The various standard states in use & the corresponding activity coefficients are clearly defined. The statistical aspect of thermodynamics is best understood once students are familiar with the rest of the book, for this reason, is treated in the last chapter. Both volumes comply with the latest IUPC recommendations for symbols. Most of the specific mathematical tools are presented either directly in the text if they are used mostly in one chapter, while the others are included in an appendix. A primarily phenomenological approach has been selected to keep chemical thermodynamics easily accessible to beginners. Intermediate steps in the derivations have been kept to enhance the clarity of the presentation. A large number of problems, most of them original, will with complete solutions, are provided. They give this textbook a great pedagogical value. This book is primarily destined to students, graduate students & practicing scientists in the fields of Chemistry, Chemical Engineering & Material Sciences.