Amines and amine derivatives are the most diverse group of epoxy curing agents. The fully polymerized epoxy resins exhibit a very wide range of thermal and mechanical properties. Though other classes of compounds (e.g., anhydrides, phenolic resins and Lewis acids) are used as hardeners for some applications, the breadth of performance imparted by amine hardeners is unmatched. This paper provides an overview of the wide variety of amine hardeners, including several recent developments that can expand the capabilities of epoxy formulators into new applications.