Set theory can be considered a unifying theory for mathematics. This book covers the fundamentals of the subject.

Daniel W. Cunningham is a Professor of Mathematics at State University of New York, Buffalo, specializing in set theory and mathematical logic. He is a member of the Association for Symbolic Logic, the American Mathematical Society, and the Mathematical Association of America. Cunningham's previous work includes A Logical Introduction to Proof, which was published in 2013.

1. Introduction; 2. Basic set building axioms and operations; 3. Relations and functions; 4. The natural numbers; 5. On the size of sets; 6. Transfinite recursion; 7. The axiom of choice (revisited); 8. Ordinals; 9. Cardinals.