However, the prime example of reference works that systematized scientific knowledge in the age of Enlightenment were universal encyclopedias rather than technical dictionaries. It was the goal of universal encyclopedias to record all human knowledge in a comprehensive reference work. The most well-known of these works is Denis Diderot and Jean le Rond d'Alembert's Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers. The work, which began publication in 1751, was composed of thirty-five volumes and over 71 000 separate entries. A great number of the entries were dedicated to describing the sciences and crafts in detail, and provided intellectuals across Europe with a high-quality survey of human knowledge. In d'Alembert's Preliminary Discourse to the Encyclopedia of Diderot, the work's goal to record the extent of human knowledge in the arts and sciences is outlined: