Preliminary Discourse to the Encyclopedia of Diderot" expresses the hopes, dogmas, assumptions, and prejudices that have come to characterize the French Enlightenment. In this preface to the "Encyclopedia, " d'Alembert traces the history of intellectual progress from the Renaissance to 1751. Including a revision of Diderot's "Prospectus" and a list of contributors to the "Encyclopedia, " this edition, elegantly translated and introduced by Professor Richard Schwab, is one of the great works of the Enlightenment and an outstanding introduction to the "philosophes.