This dictionary introduces the reader to philosophical life in the time of Henri IV, Louis XIII and Louis XIV. Not only does it consider the main streams of French philosophy in the seventeenth century (Cartesianism, Port-Royal and their followers), but it also throws light on the influence of various other families of thought. Humanism, scholasticism, the 'moralistes', the clandestine literature, theology at large are duly represented in the list of entries, but also political thought, which is too often ignored in this century of absolute monarchy, and what we may call the secret sciences (alchemy, the cabal and astrology), which played an important part in the debates of the time. The thinkers who are considered fall into the period beginning (approximately) with Pierre Charron (1541-1603) and ending with Bernard Le Bovier de Fontenelle (1657-1757).All the major seventeenth-century philosophers have their entry in the dictionary, but it also includes a very wide range of less well-known writers, many of whom have not been mentioned or covered elsewhere in philosophical reference works. These more minor figures provide irreplaceable study material for the seventeenth-century scholar. The importance of looking at minor figures is now widely accepted by historians of philosophy, and yet information on them is hard to find in the traditional sources. This Dictionary thus fills an important gap in the field of the history of French philosophy.