Mechanical Engineering deals with the design, construction, maintenance and efficient operation of machines and devices aimed at reducing human physical effort. Starting from the dawn of the civilization, humans have been using tools to augment their muscle powers. In that sense, Mechanical Engineering can be termed as the oldest discipline of engineering. Considering the available records, Archimedes (287 BC - 212 BC) appears to be the first significant contributor to Mechanical Engineering. Since his period and till 17th century, dominate sources of power have been wind and water. Although the concept of steam engine was provided in the first century, steam engines came into existence only at the end of the 17th century and played a major role to enhance the industrial productivity in the 18th century. It also provided impetus to develop thermodynamics as an important field of science and engineering. Sadi Carnot (1796-1832), who can be called as the father of thermodynamics, developed the theory with an urge to improve the efficiency of steam engines. The 19th century saw the development of internal combustion engines and electrical motors. Gradually steam engines became obsolete but steam turbines are still in vogue. Internal combustion engines and electrical motors are continuing their role of power providers to machines. One peculiar feature of Mechanical Engineering is that it is a very dynamic branch, new technologies replacing the older one at unprecedented rate. It is quick to capture the developments in Civil, Electrical, Electronics and Computer Engineering and collaborate with these branches. The 21st century is witnessing the close cooperation between Mechanical Engineering and Biotechnology. Amalgamation of Management and Mechanical Engineering led to development of engineering branches like Industrial Engineering and Production Engineering. The salient current dreams of Mechanical Engineering discipline are providing artificial intelligence to machines, developing self-replicating machines, producing all products through 3D printing and steering sustainable development.