This edition of the book serves as a text book for the first and second level courses in Engineering Thermodynamics in any undergraduate Mechanical engineering curriculum. The chapter on Exergy introduces the concept of exergy and also demonstrates in detail how it can be used to evaluate the second law efficiency of devices and cycles. The chapter on Thermodynamic cycles deals with Rankine, Brayton, Otto and Diesel cycles as well as the vapor compression refrigeration cycle. Both first and second law analysis of the cycles are presented. The chapter on Psychrometry introduces concepts relating to moist air followed by application of these concepts to examples from HVAC. The chapter on Combustion discusses combustion stoichiometry and application of first and second law to reacting systems involving solid, liquid and gaseous fuels. The chapter on Gas Phase Chemical Equilibrium introduces the notion of mechanical, thermal and chemical equilibrium and discusses in detail how equilibrium compositions of reacting mixtures are evaluated. The last chapter on Compressible Flow in Nozzles discusses in detail aspects relating to the flow of a calorically perfect gas (air) and steam in nozzles. The discussion also includes Normal shocks in the case of the former. This edition of the book also contains numerous worked examples from practical engineering applications. Hopefully, these will illustrate the application of the concepts developed in the chapters to practical situations and make the book interesting, useful and enjoyable.