This chapter examines Plato's main political ideas. It first provides a biography of Plato before discussing the overall argument of the Republic and the philosopher–kings that are its centrepiece. It then considers the Form of the good, knowledge of which is exclusive and essential to the philosopher–kings, along with the structure of the city envisioned by them, known as kallipolis, and its key operating principle. It also analyses the kallipolis from a variety of politically significant perspectives; for example, whether it is based on false ideology, whether it involves a totalitarian intrusion of the political into the private sphere, or whether it treats its least powerful members such as invalids, infants, and slaves in an unjust way. The chapter concludes by exploring how the kallipolis limits freedom of speech, artistic expression, personal freedom, and autonomy.