The Metalogicon, completed in 1159, is recognized as a landmark in the fields of philosophy, psychology, and education. Undertaken to defend the thorough study of the trivium against attack at the hands of those who wished less attention accorded to grammar, logic, and rhetoric, it is a treasure-trove of information about twelfth-century teaching as well as an enduring classic in its own right.

The study of grammar in John of Salisbury's time included familiarization with the ancient Latin classics, and involved not only a reading of them but also an analysis and imitation of their style. It thus anticipated the humanism of the Renaissance. The study of logic, as it was then pursued, comprised learning and putting into practice the principles of Aristotle's Organon.

In The Metalogicon, a leading medieval scholar summarizes the essential lineaments of existing twelfth-century education, describes his experiences while a student at Chartres and Paris, and affords personal glimpses of such contemporary intellectual leaders as Peter Abelard, Gilbert de la Porrée, and Thierry of Chartres.

John of Salisbury (ca. 1115–1176) studied with almost all the great masters of the early twelfth century, served as an aid to Thomas à Becket (1118–1170), was friend to Pope Hadrian IV, an annoyance if not an enemy to England's King Henry II, and died as Bishop of Chartres.

Daniel D. McGarry was a professor of history at Saint Louis University. He died in 1999. His translation of The Metalogicon was the first to appear in any modern language.