Paris publisher André Le Breton launches a project to translate Ephraim Chambers’ Cyclopaedia (1728) into French—an effort that soon evolves into the far more ambitious Encyclopédie enterprise.
Denis Diderot is brought into the expanding project and soon becomes central to redefining it from a translation into an original, collaborative Enlightenment reference work.
Diderot and Jean le Rond d’Alembert are appointed to lead the project editorially, establishing the partnership that shaped the early Encyclopédie (with d’Alembert overseeing the mathematical portions).
After the publication of Lettre sur les aveugles, Diderot is arrested and imprisoned at Vincennes; soon after his release he returns to intense Encyclopédie work.
Diderot publishes a Prospectus outlining the goals of the new multivolume reference work and soliciting subscribers—crucial for financing the large-scale publication.
The first text volume is published in Paris, marking the public launch of the Encyclopédie as a subscription venture and immediately drawing scrutiny from religious and state authorities.
Following the appearance of early volumes, official pressure leads to a temporary suspension and heightened censorship threats; publication nevertheless resumes and continues through the mid-1750s.
Robert-François Damiens attempts to assassinate Louis XV, and authorities increasingly link fears of “subversive” ideas to Enlightenment publishing—adding momentum to attacks on the Encyclopédie and related works.
Discouraged by controversy and other pressures, d’Alembert resolves to leave the Encyclopédie project (and later departs definitively), increasing Diderot’s editorial burden.
Louis de Jaucourt becomes the project’s most prolific contributor, particularly in the later text volumes; his sustained output helps the enterprise survive political and clerical attacks.
The French Royal Council withdraws the publication privilege and forbids distribution and reprinting; the project continues under tacit tolerance, with work shifting toward less politically sensitive components such as the plates.
With text publication constrained, the illustrated plates—depicting trades, crafts, and industrial processes—become a practical route to keep the broader enterprise moving forward.
Diderot learns that publisher-printer André Le Breton and a compositor had removed or softened controversial passages in multiple volumes without his approval—fueling Diderot’s bitterness about the project’s compromises.
The main sequence of 17 text (letterpress) volumes is brought to completion, closing the primary editorial phase of the undertaking that Diderot had driven for nearly two decades.
The last of the plates volumes appears, completing the first-edition publication program: 17 text volumes (1751–1765) and 11 volumes of plates (1762–1772).
Denis Diderot and the Encyclopédie project (1746–1772)
