Rene Descartes was a French philosopher and mathematician who is widely regarded as one of the most influential figures in the history of philosophy and mathematics. He is best known for his philosophical work, which includes the famous statement 'I think, therefore I am, ' as well as his development of Cartesian dualism, which posits that the mind and body are two distinct entities. He also made significant contributions to mathematics, including the development of analytic geometry and the Cartesian coordinate system.