Based on the “Encyclopédie” of Diderot and D’Alembert this article examines the attitude to the mind and books during the Age of Enlightenment in France. We consider the Enlightenment as the period of 18th century up to French Revolution and in France only. The mind occupied one of the main positions in the Enlightenment thought. The purpose of our article is to explore the connection between mind and books using the Encyclopédie of Diderot and D’Alembert as the most important sources of the era. The Encyclopédie emphasized the importance of access to knowledge, and therefore to the book, as a repository of this knowledge. The article shows the functions and purpose of books from the point of view of Enlightenment thinkers. The features according to which the quality of publications was assessed are highlighted. A critical approach to the content of books is emphasized. We show the cases where the love of books was appreciated, as well as cases when the love was condemned. The article defines ways of writing a good book from the point of view of Enlightenment thinkers. This study emphasized that bibliomaniacs - people obsessed with books and frenzied desire to collect them - were especially blamed. It is shown that a passion for books led to stinginess. In addition, the article provides a systematization of scientific knowledge on the example of a catalog system. The conclusion contains provisions on the influence of books on the human mind.