What in the Heck Category theory is a (relatively) nascent branch of mathematics that provides a fundamental framework for describing abstract structures in mathematics that serve as the building blocks for all mathematics; it contends set theory in this regard. This provides an excellent segway into aptly describing what these two paradigms focus in on: unlike set theory, category theory concerns the relation between elements (called objects). This necessitates expounding upon by explaining the three most important concepts in category theory.