Descartes intended to revolutionize seventeenth-century philosophy and science. But first he had to persuade his contemporaries of the truth of his ideas. Of all his publications, Meditations on First Philosophy is methodologically the most ingenuous. Its goal is to provoke readers, even recalcitrant ones, to discover the principles of “first philosophy.” The means to its goal is a reconfiguration of traditional methodological strategies. The aim of this chapter is to display the methodological strategy of the Meditations. The text’s method is more subtle and more philosophically significant than has generally been appreciated. Descartes’ most famous work is best understood as a response to four somewhat separate philosophical concerns extant in the seventeenth century. Section 1 describes these. Section 2 discusses how Descartes uses and transforms them. A clearer sense of the Meditations’ methodological strategy provides a better understanding of exactly how Descartes intended to revolutionize seventeenth-century thought.