This document provides an introduction to microeconomics. It defines economics as the study of how individuals and societies choose to employ scarce resources. It discusses four main definitions of economics from classical economists like Adam Smith to modern economists. It then distinguishes between microeconomics and macroeconomics, with microeconomics focusing on individual units like firms and resource allocation, and macroeconomics studying overall aggregates like total production and consumption. The document also covers different types of economies (capitalist, socialist, mixed), central economic problems of resource allocation, and production possibility curves to illustrate scarcity.