Agent-based computational economics (ACE) is the computational modeling of economic processes (including whole economies) as openended dynamic systems of interacting agents (Tesfatsion 2016a). In this book, author Shu-Heng Chen—an important pioneering contributor to the development of ACE—undertakes a detailed exposition of the ACE modeling approach that focuses on two fundamental questions. First, what is ACE? Second, to what extent is ACE useful, or even necessary, for understanding economic processes?