This videotape captures a lively, vivid, and meticulously researched lecture by the noted mathematical historian Judith Grabiner. In looking at Descartes' approach to problem solving, Grabiner brings into focus his general philosophy that, unless one has method, one will never discover anything useful. His general method was to reduce a geometric problem to an algebraic one and then construct a curve that solves the algebraic problem. Grabiner demonstrates how Descartes used this method in a particular situation. Connecting this mode of thinking to the history that preceded Descartes, she shows how he combined, extended, and exploited earlier methods.