It is a comprehensive account of the subject dealing with Fundamental Concepts, Thermodynamic Law, Thermodynamic Functions, Elementary Information about Statistical Thermodynamics; Systems of Variable Composition-Colligative Properties of Ideal Solution, Principles of Purification Techniques like Fractional Distillation, Steam Distillation, Fractional Crystallization and Zone Refining, Chennai Equilibria and Phase Rule upto Three Component Systems. The logical approach and simple style of the book makes it essential to B.Sc. (Hons & General) and M.Sc. students of all Indian universities and a useful reference book for students of Physics and Chemical Engineering.