Plato's Republic, Hobbes's Leviathan, and Marx's Communist Manifesto are universally acknowledged classics of Western political thought. But how strong are the core arguments on which they base their visions of the good society that they want to bring into being? In this lively and provocative book, W. G. Runciman shows where and why they fail, even after due allowance has been made for the different historical contexts in which they wrote. Plato, Hobbes, and Marx were all passionately convinced that justice, peace, and order could be established if only their teachings were implemented and the right people put into power. But Runciman makes a powerful case to the effect that all three were irredeemably naive in their assumptions about how human societies function and evolve and how human behavior could be changed. Yet despite this, Runciman insists that Republic, Leviathan, and The Communist Manifesto remain great books. Born of righteous anger and frustration, they are masterfully eloquent pleas for better worlds--worlds that Plato, Hobbes, and Marx cannot bring themselves to admit to be unattainable.