Isaac Newton's work laid the groundwork for modern engineering. Isaac Newton was a physics, astronomer, theologian, alchemist and mathematician at the turn of the 18th century. His Philosophi Naturalis Principia Mathematica, published in 1687, is considered to be the most influential book in the history of science. It laid the groundwork for the modern subject of calculus. In this work Newton discusses universal gravitation and the three laws of motion. The first volume of A Commentary On Newton's Principia attempts to explain Newton's work and is designed for University students. The second volume is a supplement to the first.