The aim of this thesis has been to argue, on the basis of primary sources, that Huygens was a pioneer in the field of mechanical engineering. He fits the definition of a mechanical engineer as somebody who develops a novel invention either empirically or theoretically, using known mechanical theories. In the same way, a new invention may come about through transforming an existing machine or instrument thus revolutionizing any future versions of it. Huygens did both he applied a pendulum to existing clocks and transformed the making of precision instruments from that moment onwards. The first chapter of the thesis presents Huygens' works on pendulum clocks and marine clocks. The second chapter is dedicated to Huygens' research and designs of the air pump and linking with the third chapter on matter theory. The fourth chapter focuses on Huygens' designs of various instruments (the telescope, the microscope, the level, the planetarium and others). The final chapter depicts Huygens in the societies in which he lived. Huygens was a pioneer of mechanical engineering because he presented a complete work on mechanics to explain instruments, 'automata', by mathematical axioms and laws. Furthermore, he developed a methodology for improving instruments and machines based on searching for the best materials to obtain the best working models. The Horologium Oscillatorium of 1673, was a textbook, which inspired others to continue a tradition of mechanics for the mechanical engineer. With geometrical ratios he was able to show the applicability of technology in everyday life. Therefore, Huygens took the foundations of mechanics further than his contemporaries did. The geometry he used was the basis, which could simplify and give a quantitative measure of nature and of any man-made instruments alike.