Mathematical Treasures - Rene Descartes' Treatise on Method

This is the title page to René Descartes' Discourse on Method or Treatise on Method, with its three famous essays on Dioptrics (or Optics), Meteorology, and Geometry.  The third essay contains Descartes' treatment of analytic geometry as well as his theory of equations and his rule for finding the normal to a given curve. 

A complete translation of the Treatise with the essays is in René Descartes, Discourse on Method, Optics, Geometry, and Meteorology, translated by Paul Olscamp (Indianapolis, Bobbs-Merrill Co., 1961). 

Index to Mathematical Treasures​