This is a general introduction to Plato's political thought. It covers the main periods of Platonic thought, examining those dialogues that best show how Plato makes the city's unity the aim of politics and then makes the quest for that unity the aim of philosophy. From the psychological model (the city is like a great soul) to the physiological definition (the city is a living being), the reader can traverse the whole of Plato's oeuvre, and understand it as a political philosophy. The book is designed to be an undergraduate textbook but will also be of interest to scholars. It is an English translation of Platon et la cité, published in French by Presses Universitaires de France in 1997 as part of the series Philosophies, and offers English-speaking readers access to a more unifying continental European reading of Plato than is common in UK or North American scholarship.