Top: Kids and Teens: School Time: Math: Mathematicians: Descartes, René (5)
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René Descartes' Life and Works - Provides a detailed look at his life and writings.

Encarta: Descartes, René - Encyclopedia articles summarizes his influence on math, philosophy, and science.

René Descartes - An eighth-grader introduces the man who said, "I think; therefore, I am."

René Descartes - Biography from the MacTutor History of Mathematics archive.

Rene Descartés (1596-1650) - Short profile along with links to some of his works.