This little book is a brief introduction to logic, the study of the rules of thought, as approached from the perennial Catholic tradition. It explores the three operations of thought (apprehension, judgment, and reasoning); syllogisms and their figures; common fallacies; the methods of inductive reasoning; and even a brief introduction to dialectic. It also contains a full set of exercises, with answers, for those who wish to test their understanding in the deductive section. A modern, approachable introduction to this vitally important subject.