ROUNG PUBLICATION This book is introduction to the fundamental concepts and tool needed for the engi-neering approach of thermodynamics. It attempt to fill the gap between the branch of physical science that deals with the relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the rela-tionships between all forms of energy. Although thermodynamics developed rapidly during the 19th century in response to the need to optimize the performance of steam engines, the sweeping generality of the laws of thermodynamics makes them applicable to all physical and biological systems. In particular, the laws of thermodynamics give a complete description of all changes in the energy state of any system and its ability to perform useful work on its surroundings. This book covers classical thermodynam-ics, which does not involve the consideration of individual atoms or molecules. Such concerns are the focus of the branch of thermodynamics known as statistical ther-modynamics, or statistical mechanics, which expresses macroscopic thermodynamic properties in terms of the behaviour of individual particles and their interactions. It has its roots in the latter part of the 19th century, when atomic and molecular theories of matter began to be generally accepted. The Book designed for students of engineering. The three laws of thermodynamics (zeroth, first, and second) will be explored in detail, and the properties of material will be studied., and second) will be explored in detail, and the properties of materials will be studied. Many useful relation will be derived. It Contain the topics like * Basic concepts and definitions * The work interaction * The first law, energy, & the heat interaction * The zeroth law, temperature, & scales of temperature * Properties of gases and liquids, equations of state * The second law, thermodynamic temperature scales, & entropy * Relations between properties * Open thermodynamic systems * Availability & Irreversibility There will be emphasis on problem-solving. Students will need to spend significant effort on solving exercises.