This document provides an overview of managerial economics. It defines managerial economics as the application of economic principles and analysis to business decision-making. It discusses how managerial economics uses hypothetical models and the scientific method to understand firm behavior, make predictions, and test those predictions against evidence. While the assumptions of models may not be realistic, the goal is explanatory and predictive power rather than descriptive accuracy. Managerial economics aims to understand what is, while related fields like industrial organization and management science also aim to provide prescriptive guidance on what should be done.