Politics invades much of our daily lives. Whether we are actively engaged in politics or not, it is difficult to interact on social media, watch television, or even have a casual conversation without political topics creeping in. Many of the things integral to our lives, such as getting an education, working, or even traveling, are dependent upon political systems. However, we rarely think about what grounds these systems. This chapter examines that grounding by introducing political philosophy. A branch of philosophy that looks at how society determines governance, political philosophy also considers core concepts such as justice, citizenship, and authority; investigates questions of legitimacy in political institutions; and examines the rights, freedoms, and responsibilities a citizen may hold in a society. This chapter begins by looking at a few key historical figures from different parts of the world and discovering how they pictured an ideal society. Next, it examines different types of rule and theories about how best to govern a society and address the roles leaders and citizens play. Finally, the chapter looks at some of the issues currently being discussed by political philosophers.