The primary purpose of this book is to present some of the key economic concepts that have guided economic thinking in the last century and to identify which of these concepts will continue to direct economic thought in the coming decades. This book is written in an accessible manner and is intended for a wide audience with little or no formal training in economics. It should also interest economists who want to reflect on the direction of the discipline and to learn concepts and achievements in other subfields. The author imparts his enthusiasm for the economic way of reasoning and its wide applicability. Through the abundant use of illustrations and examples, the author makes concepts understandable and relevant. Topics covered include game theory, the new institutional economics, market failures, asymmetric information, endogenous growth theory, general equilibrium, rational expectations, and others.