We all agree that these words matter, and yet they mean very different things to different people. Such radically different things, in fact, that individuals, protest movements, and entire states are sometimes prepared to go to war to resolve their understanding of, say, "freedom" over somebody else's. In this course, we will explore how and why words come to mean such different things across time and space. It is not just a learning experience. To understand the social life of political ideas, we'll be drawing on the vast collections of the British Library.