DIDEROT (Denis), ALEMBERT (Jean Le Rond d'), et al. Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers par une société de gens de lettres. 32 (out of 33) vol. in-folio (39 x 24,6 cm), marbled calf, spine ribbed and decorated with gilt motifs, red title-pieces and brown tomaison (contemporary binding). First edition of this monumental publishing venture, unique of its kind and emblematic of the spirit of the Enlightenment. This copy contains 17 volumes of text, 10 (of 11) volumes of plates and 5 volumes of supplements, one of which contains plates. The 10 (of 11) volumes of plates contain 2,321 (of 2,580) copper-engraved plates, 244 of which are double, triple or even quadruple-page plates. The Supplement volume containing the plates contains 215 more, including 29 double or folded plates, making a total of 2536 plates for this copy, as well as the beautiful and famous frontispiece engraved by B.-L. Prévost after Charles-Nicolas Cochin fils and some printed tables. (For the sake of clarity, we have counted each plate, whether single, double, triple or quadruple, as a plate, unlike the publishers). "A monument and signpost in the history of European thought; the acme of French Enlightenment; a herald of the French revolution; and a permanent source for all aspects of eighteenth-century civilization" (Printing and the Mind of Man). This publishing venture, with all its developments, took 30 years to complete. "Under the direction of Diderot and d'Alembert, more than two hundred known collaborators worked on this undertaking, one of the most ambitious that French publishing attempted under the Ancien Régime" (Jacques Proust, En français dans le texte). The 11th volume of plates is missing. Bindings worn, three upper boards detached, spotting and a few leather tears, notably on the spine. Some light foxing, a little more present in the text volumes, rare plates a little short in the gutter, one plate widely torn, without missing; a bifolium dislocated in volume XVI, frontispiece partially dislocated, one anatomy plate tiled in pencil. Bibliography: D. Adams, Bibliographies des œuvres de Denis Diderot (1739-1900), Ferney-Voltaire, 2000, tome 1. Printing and the Mind of Man, no. 343. En français dans le texte, no. 156.