The realms of political thought or political philosophy are introduced with an emphasis on the major modern political ideologies (liberalism, conservatism and socialism) and their main proponents (Locke, Burke and Marx, respectively). The chapter also describes the American versions of liberalism and conservatism and explores how modern political ideologies continue to evolve and new ideologies emerge. This edition delves more deeply into the origins of both modern and classical political thinking.  Ideologies serve many masters and the chapter discusses the uses and misuses of broad political philosophies.