We have entered a period of renewed nationalism and ethnic conflict in the post-Cold War world. But what exactly is nationalism? Anthony Smith, a British sociologist, is a longtime student of this question. His latest book, examining the nature, causes and consequences of national identity, could not be more relevant to our times. Nations and nationalism, he argues, are not simply political bodies and ideology, but cultural phenomena. They are multidimensional and encompass language, sentiments and symbolism. Thus the Basques, Kurds and Tamils form a clear national identity even without a state of their own, recognition of which contributes to turmoil and conflict. Julia Kristeva addresses the question from quite another perspective, that of a French psychoanalyst and linguistics expert. She writes about people's feelings of "otherness" or "strangeness." When confronted with an environment different from their own, they withdraw into their familiar ethnicity. Nationalism then becomes a form of "defensive hatred" and, in her thinking, is associated with jingoism, skinheads and extremes. In this short, very personal essay she appeals for a cosmopolitanism that transcends today's more virulent forms of nationalism.