The Encyclopédistes (French: [sikl?pedist]) (also known in British English as Encyclopaedists, or in U.S. English as Encyclopedists) were members of the Société des gens de lettres, a French writers' society, who contributed to the development of the Encyclopédie from June 1751 to December 1765 under the editors Denis Diderot and Jean le Rond d'Alembert.
The composition of the 17 volumes of text and 11 volumes of plates of the Encyclopédie was the work of over 150 authors belonging, in large part, to the intellectual group known as the philosophes. They promoted the advancement of science and secular thought and supported tolerance, rationality, and open-mindedness of the Enlightenment.
More than a hundred encyclopédistes have been identified. They were not a unified group, neither in ideology nor social class. Below some of the contributors are listed in alphabetical order, by the number of articles that they wrote, and by the identifying "signature" by which their contributions were identified in the Encyclopédie.
Beyond the known collaborators - at least in name - many articles are not signed and certain authors expressed a desire to remain anonymous. Other authors, Allard or Dubuisson for example, remain a mystery to us. Moreover, the sporadic research into the quotations, borrowings, and plagiarisms in the Encyclopédie - the illustrations as well as the text - illuminate a group of "indirect" collaborators.
Among some excellent men, there were some weak, average, and absolutely bad ones. From this mixture in the publication, we find the draft of a schoolboy next to a masterpiece.
Diderot had just finished the translation of A Medicinal Dictionary by Robert James when the publicist André le Breton charged him, on 16 October 1747, to resume the project of translating the English Cyclopaedia that Jean Paul de Gua de Malves could not successfully complete. Diderot undertook the history of ancient philosophy, wrote the Prospectus and the System of Human Knowledge, and, with D'Alembert, revised all the articles.
Louis de Jaucourt is little known in other respects but was one of the principal authors in the disciplines of economics, literature, medicine, and politics.
Jean le Rond d'Alembert is the author of the Preliminary Discourse and of several articles. In 1752 d'Alembert, who was tired of the mocking, cries of indignation, and religious persecution against the Encyclopédie, retired from the encyclopedic undertaking. Subsequently, his contributions were limited to the subject of mathematics, a sensible topic in the eyes of censors.
In the Encyclopédie, the authors are identified by a letter at the end of an article.