This book presents the rich fabric of language, clothing, food, and architecture which forms the diverse religious, political, cultural and ethnic identities of humanity. The colour of a scarf, the accent of a conversation, can unite people or divide them, and the smallest detail can play its part in signalling who are allies and who are enemies, as much for elites as for citizens in a democracy. Human identity is neither rigidly determined nor unpredictable and spontaneous, but between those two extremes is the forum on which the public life of humanity is generated. After a century in which an assumption was held across the ideological spectrum from left to right and from Marxists to economic individualists that the rational pursuit of material gain underlay social and political activity, the fundamental importance of the cultivation and preservation of identity is re-emerging across the whole spectrum of politics in which Britain is one example only. Yet while identity is the dimension in which public life is conducted, it is inherently paradoxical: on the one hand people cultivate their identity by association with a group, or religion, or nation, whilst on the other hand they distinguish themselves from their associates within those groups by presenting an intensified or purer form of the qualities which otherwise unite them. So identity simultaneously generates equality and inequality, between identification by association, and identity by exclusion and differentiation; it is both the engine of public life, and the cause of its confusion and conflict. This Open Access edition was funded by London School of Economics and Political Science.