Topics in Logic: This book introduces the reader to some basic concepts in mathematical logic and propositional calculus. Topics in formal theories are briefly analyzed. First-order predicate calculus is described including some of its interpretations in arithmetic and set theory. Axiomatic set theories are covered. Some examples of axiomatic set theories are also illustrated. Relations are defined along with basic concepts of homomorphism and congruence. Finally universal algebras are defined and some of their properties discussed.