[en] The Encyclopedie (1751-1772), conceived and directed by Diderot and d'Alembert, was intended to be a critical compendium of all the learning of the time and to provide society with a rational knowledge free from dogma and superstition. It was produced with private capital and involved a large team of distinguished scientists and philosophers. It consists of 17 volumes of text and 11 of plates. At the time geology was in its infancy and the Encyclopedie collects together works by Agricola, Steno, Lehman and Wallerius. The French geologist Nicolas Desmarest (1725-1815) studied the volcanic area of Auvergne in the Central Massif of France, his ideas on volcanism and the internal structure of the Earth can be found in the Encyclopedie, which would later be published separately. Although it does not contribute much that is new to the Earth sciences, it is important in helping us to assess the environment in which the Encyclopaedists moved and better appreciate what their critical spirit and fight against dogmatism represented in the creation of modern thought. (Author)