---

In his monumental 1687 work Philosophiae Naturalis Principia Mathematica, known familiarly as the Principia, Isaac Newton laid out in mathematical terms the principles of time, force, and motion that have guided the development of modern physical science. Even after more than three centuries and the revolutions of Einsteinian relativity and quantum mechanics, Newtonian physics continues to account for many of the phenomena of the observed world, and Newtonian celestial dynamics is used to determine the orbits of our space vehicles. This completely new translation, the first in 270 years, is based on the third (1726) edition, the final revised version approved by Newton; it includes extracts from the earlier editions, corrects errors found in earlier versions, and replaces archaic English with contemporary prose and up-to-date mathematical forms.

---

I. Bernard Cohen (1914-2003) was Victor S. Thomas Professor (Emeritus) of the History of Science at Harvard University. Among his recent books are Benjamin Franklin´s Science (1996), Interactions (1994), and Science and the Founding Fathers (1992). Anne Whitman was coeditor (with I. Bernard Cohen and Alexander Koyré) of the Latin edition, with variant readings, of the Principia (1972). Julia Budenz, author of From the Gardens of Flora Baum (1984), is a multilingual classicist and poet.

---