This document discusses topological insulators, beginning with an overview of the integer quantum Hall effect and how topology relates to boundary states. It then covers how spin-orbit coupling allows for topological insulator phases even with time-reversal symmetry. Several key papers on topological insulators are referenced, including the discovery of the quantum spin Hall effect and theoretical descriptions of topological phases in two and three dimensions. Experimental observations of topological insulator materials via angle-resolved photoemission spectroscopy are also summarized.