Colin Maclaurin (1698–1746) was a leading Scottish mathematician and a key proponent of Newtonian physics in the Enlightenment. He was Professor of Mathematics at the University of Edinburgh and a Fellow of the Royal Society. This work is posthumous, edited and published by Patrick Murdoch from Maclaurin’s manuscript papers, and was printed to support Maclaurin’s children. It is amongst the most important early works meant to make Newton’s discoveries accessible to educated readers. It discusses optics, gravity, mechanics, and mathematics, placing Newton’s achievements in context and defending them from critics.