The article examines the tradition of the writing of Encyclop?dias and historical dictionaries in seventeenth and eighteenth century France. The main ones—by Bayle, Chambers, and by the group assembled by d’Alembert and Diderot—are all connected with unorthodoxy in religion. The massive collection of knowledge that all three dictionaries compiled sometimes seems to allow a juxtaposition of ideas which cannot be properly reconciled-a situation which leaves it to the reader to create a coherent whole. But Diderot goes the farthest in this direction, and causes even the possibility of such a whole to be questioned.