Topological order describes a new class of quantum states of matter that are characterized by their rich entanglement patterns. One consequence of this complicated internal entanglement structure is the appearance of non-Abelian statistics. Chern-Simons theory plays a crucial role in discovering non-Abelian statistics and non-Abelian topological order in condensed matter systems. I will discuss how non-Abelian Chern-Simons theory entered condensed matter physics.