Book excerpt: 2014 Reprint of 1948 Third Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. The "Trivium" is a systematic method of critical thinking for deriving certainty from any information coming into the mind via the five senses. In medieval universities, the Trivium comprised the three subjects that were taught first, specifically in this order: grammar, logic and rhetoric. While most textbooks are lucky to enjoy a shelf life of three or four years, "The Trivium" followed a different path. In 1947, when Columbia University Press published her celebrated dissertation, "Shakespeare's Use of the Arts of Language," Sister Miriam Joseph's previously published textbook gained wider notice. And since then, The "Trivium" continues to be rediscovered by new generations of writers and teachers. This dense, authoritative textbook takes all of Aristotle's teachings on logic, grammar, and rhetoric, and some of his teachings of poetics, adds some of the insights gained in the subsequent centuries, and presents it in a well-organized flow.