June 28, 1751

Encyclopédie

Volume I of Diderot and d’Alembert’s Encyclopédie appears in Paris

Subscribers had already paid 60 livres. Collecting the first volume required another 36.

June 1751: the first delivery

Volume I of the Encyclopédie appeared in Paris in 1751 together with d'Alembert's Preliminary Discourse. The University of Michigan's scholarly edition dates their appearance to 28 June.

The title page identified Denis Diderot as the work's organizer and publisher and Jean le Rond d'Alembert as responsible for its mathematical portion. Briasson, David l'aîné, Le Breton and Durand were the named Paris booksellers.

What came before the letter A

Ahead of the alphabetical entries, readers met d'Alembert's Preliminary Discourse, a revised version of Diderot's prospectus, a contributor list, explanations of the system of knowledge, observations on Bacon's division of the sciences, and the celebrated knowledge tree.

Subscribers had already paid 60 livres; taking delivery of Volume I cost another 36. The prospectus had advertised ten folio volumes — eight of text and two of plates, containing 600 plates.

A print run overtaken within a month

Volume I was printed in a little over 2,000 copies. The critical ENCCRE edition reports nearly 1,500 subscribers by July 1751.

The exact day is not settled. June 28 comes from the University of Michigan edition and the title page is dated June 1751, but ENCCRE and the BnF give only June 1751, and another scholarly publication dates Le Breton's issue to 1 July.

The difference may be between appearance and formal release or sale.

Sources

Researched 24 Aug 2026 7 sources not yet audited Date disputed

How this was checked

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Date disputed. Sources disagree about when this happened.

What the sources leave uncertain

June 28 is specifically supported by the University of Michigan’s scholarly edition, and the title page is dated June 1751. ENCCRE and the BnF give only June 1751, while another scholarly publication dates Le Breton’s issue to July 1. The exact day may distinguish appearance from formal release or sale.
Because of that conflicting July 1 date, June 28 should not be treated as unanimously established even though it is the strongest specific date found.