This document is a chapter from the textbook Magruder's American Government on political parties. It is divided into 5 sections that discuss: 1) what parties are and their functions, 2) the two-party system in the US, 3) the history of parties in the US, 4) minor parties, and 5) party organization. The chapter explains that political parties seek to control government by winning elections, the US has historically had a two-party system, and the first parties were the Federalists and Anti-Federalists, followed by periods of dominance by the Democrats and Republicans. It also outlines the roles of minor parties and how the major parties have a decentralized structure at the national, state, and local levels.