This book provides the beginner in formal logic with a short introduction that is thorough enough on important points to offer a basis for the study of more advanced works. The first four chapters give an account of the calculus of propositions, and the next two give an outline of the predicate calculus in which special attention is given to the basic notion of satisfiability. An appendix sketches the traditional doctrine of the syllogism and its relation to the Boolean algebra of classes. No previous knowledge of logic is assumed, although the historical first section of Chapter I will be of interest chiefly to those students who have some acquaintance with the traditional logic of the syllogism. Chapter IV was extensively revised for the Second Edition. The present edition incorporates a number of minor corrections and amendments. Bibliographical notes to the chapters have been added to guide the students' further reading and exercises have been provided. It should be emphasised that the working of exercises is just as essential to the understanding of the bookwork in elementary logic as it is in mathematics.