<b>The Mathematical Principles of Natural Philosophy by Isaac Newton</b>&nbsp;often referred to as simply the&nbsp;<b><i>Principia</i></b>&nbsp;(/pr?n's?pi?,&nbsp;pr?n'k?pi?/), is a work expounding&nbsp;Newton&#39;s laws of motion&nbsp;and his&nbsp;law of universal gravitation; in three books written in Latin, first published 5 July 1687.<br /><br />After annotating and correcting his personal copy of the first edition, Newton published two further editions, during 1713 with errors of the 1687 corrected, and an improved version of 1726.<br />The&nbsp;<i>Principia</i>&nbsp;forms the foundation of&nbsp;classical mechanics. Among other achievements, it explains&nbsp;Johannes Kepler&#39;s&nbsp;laws of planetary motion, which Kepler had first obtained&nbsp;empirically.<br /><br />The&nbsp;<i>Principia</i>&nbsp;is considered one of the most important works in the&nbsp;history of science. The French mathematical physicist&nbsp;Alexis Clairaut&nbsp;assessed it in 1747: &quot;The famous book of&nbsp;<i>Mathematical Principles of Natural Philosophy</i>&nbsp;marked the epoch of a great revolution in physics. The method followed by its illustrious author Sir Newton ... spread the light of mathematics on a science which up to then had remained in the darkness of conjectures and hypotheses.&quot;<br /><br />A more recent assessment has been that while acceptance of Newton&#39;s theories was not immediate, by the end of the century after publication in 1687, &quot;no one could deny that&quot; (out of the&nbsp;<i>Principia</i>) &quot;a science had emerged that, at least in certain respects, so far exceeded anything that had ever gone before that it stood alone as the ultimate exemplar of science generally&quot;.