Thermodynamics is the branch of science that describes the basic laws and principles governing the processes of transfer and transformation of energy along with the changes in properties of the substances affected by such processes. The laws are formulated from observations in nature. The basic principles as corollaries of the laws are established through logical deductions following the laws. The science of thermodynamics also provides the relationships of the properties of substances for their use in determining the changes of properties in physical processes performed by the substances. The subject thermodynamics is of prime importance as a foundation pillar of all branches of engineering, since technological processes and their developments involve transfer and transformation of energy. In the present course we will discuss the laws of thermodynamics and its corollaries. The discussion will be based on physical concepts, mathematical expressions and illustrated examples of practical applications. This will not only clear the physical concepts of the students but will enable the students to get rid of usual misleading concepts in understanding the laws and their applications.