SOURCE: "System of the World," in Books That Changed the World, Second Edition, American Library Association, 1978, pp. 334-74.

In the following essay, Downs surveys the content, scope, and reception of Newton's Principia.

Gi; sir Isaac Newton. Principia Mathematica =~ Ssir Isaac Newton. Principia Mathematica

Of all the books which have profoundly influenced human affairs, few have been more celebrated and none read by fewer people than Sir Isaac Newton's Philosophiae Naturalis Principia Mathematica ("Mathematical Principles of Natural Philosophy"). Deliberately written in the most abstruse and technical Latin, profusely illustrated by complex geometrical diagrams, the work's direct audience has been limited to highly erudite astronomers, mathematicians, and physicists.

One of Newton's chief biographers has stated that when the Principia was published in the last quarter of the seventeenth century there were not more than three or four men living who could comprehend it; another generously stretched the number to ten...