Thermodynamics is the study of heat (thermo) and work (dynamics). Thermodynamics is the branch of physics that deals with the relationships between heat and other forms of energy. In particular, it describes how thermal energy is converted to and from other forms of energy and how it affects matter. It was born in the 19th century as scientists were first discovering how to build and operate steam engines. Thermodynamics deals only with the large scale response of a system which we can observe and measure in experiments. Small scale gas interactions are described by the kinetic theory of gases. The methods complement each other; some principles are more easily understood in terms of thermodynamics and some principles are more easily explained by kinetic theory. Thermodynamics, then, is concerned with several properties of matter; foremost among these is heat. Heat is energy transferred between substances or systems due to a temperature difference between them. As a form of energy, heat is conserved, (ie: it cannot be created or destroyed). It can, however, be transferred from one place to another. Heat can also be converted to and from other forms of energy. This book concentrates on a wide range of applications of thermodynamics, gathers a series of contributions by the scientists in the world, gathered in a systematic manner. It can be used in post-graduate courses for students and researchers to whom the thermodynamics is one of the areas of interest.