This document provides an introduction to comparative politics and key definitions. It discusses three approaches to studying comparative politics: political systems, political behavior, and institutional approaches. It also defines key political science concepts like the state, sovereignty, nationalism, and different models of the relationship between states and nations. The document outlines different types of political systems such as unitary states, federations, and confederations. It also discusses concepts like constitutions, regimes, ideologies, and separations of power.