This document provides an overview of key economic concepts including: 1) It distinguishes between microeconomics, which studies small economic units like consumers and businesses, and macroeconomics, which studies a country's overall economic issues. 2) It describes the four types of market structures in private enterprise systems and the three major types of economic systems. 3) It identifies the four stages of the business cycle and explains how monetary and fiscal policy can be used to manage an economy's performance. 4) It notes that the major global economic challenges of the 21st century will require international cooperation and new policy approaches.