The Encyclopaedia (1751-1765) has rightly been pronounced the central work of the rationalistic movement which made the France of 1789 so different from the France of 1715. [Footnote: The general views which governed the work may be gathered from d'Alembert's introductory discourse and from Diderot's article Encyclopedie. An interesting sketch of the principal contributors will be found in Morley's Diderot, i. chap. v. Another modern study of the Encyclopaedic movement is the monograph of L. Ducros, Les Encyclopidistes (1900). Helvetius has recently been the subject of a study by Albert Keim (Helvetius, sa vie et son oeuvre, 1907). Among other works which help the study of the speculations of this age from various points of view may be mentioned: Marius Roustan, Les Philosophes et la societe francaise au xviii siecle(1906); Espinas, La Philosophie sociale du xviii siecle et la Revolution (1898); Lichtenberger, Le Socialisme au xviii siecle(1895). I have not mentioned in the text Boullanger (1722-1758), who contributed to the Encyclopaedia the article on Political Economy (which has nothing to do with economics but treats of ancient theocracies); the emphasis laid on his views on progress by Buchez (op. cit. i. III sqq.) is quite excessive.] It was the organised section of a vast propaganda, speculative and practical, carried on by men of the most various views, most of whom were associated directly with it. As has well been observed, it did for the rationalism of the eighteenth century in France much what the Fortnightly Review, under the editorship of Mr. Morley (from 1868 to 1882) did for that of the nineteenth in England, as an organ for the penetrating criticism of traditional beliefs. If Diderot, who directed the Encyclopaedia with the assistance of d'Alembert the mathematician, had lived a hundred years later he would probably have edited a journal.