This is probably the clearest book ever written on symbolic logic for the philosopher, the general scientist, and the layman. For years it has received the appreciation of those who have been rebuffed by other introductory works because of insufficient mathematical training. No special knowledge of mathematics is required here; even if you have forgotten most of your high school algebra, you can learn to use mathematical logic by following the directions in this book. Now revised and corrected, the book allows you to start with the simplest symbols and conventions and end up with a remarkable grasp of the Boole-Schroeder and Russell-Whitehead systems. It covers the study of forms, essentials of logical structure, generalization, classes, and the principal relations among them, universe of classes, the deductive system of classes, the algebra of logic, abstraction and interpretation, calculus of propositions, the assumptions of Whitehead and Russell's Principia Mathematica, and logistics. Appendices cover symbolic logic and the logic of the syllogism, the construction and use of truth-tables, and proofs of two theorems. "One of the clearest and simplest introductions to a subject which is very much alive." — Mathematics Gazette.