Thermodynamics is a branch of physics that studies the relationship between heat, work, temperature and energy, entropy, radiation and the physical properties of matter. It majorly focuses on the transfer of energy from one form to another and from one place to another. Thermodynamics is principally based on a set of four laws that govern the behavior of physical quantities such as heat, work, temperature and energy. The two properties of thermodynamics include enthalpy and entropy, which may be extensive or intensive. Enthalpy is defined as measurement of energy in a thermodynamic system. Entropy is a thermodynamic function that measures the randomness or disorder. These properties are capable of specifying the state of the system. Thermodynamics is applied in various fields such as physical chemistry, biochemistry, chemical engineering and mechanical engineering. This book is compiled in such a manner, that it will provide an in-depth knowledge about the subject of thermodynamics. It will serve as a valuable source of reference for graduate and postgraduate students.