Nobel Prize winning economist Sen deplores the "little boxes" that divide us in this high-minded but seldom penetrating brief against identity politics. Sen observes that ideologies of hate typically slot people into communities based on a single dimension that trumps the multifaceted affinities of class, sex, politics and personal interest that make up individual identities. This "reductionist" us-versus-them outlook is not limited to jihadists, he argues, but is a widespread intellectual tendency seen in Samuel Huntington's "clash of civilizations" paradigm, in postcolonial critiques of democracy and rationalism as "Western" ideals, as well as in efforts to "dialogue" with moderate Muslims. (These last, he feels, pigeonhole Muslims in purely religious terms.) Sen rebuts the "singular affiliation" falsehood with a cursory historical, literary and cultural survey of the diversity of supposedly monolithic civilizations (Akbar, a 16th-century Mughal emperor and champion of religious toleration, is a favorite citation.) Sen's previous work (Development as Freedom) injected liberal values into development economics; here, he argues that the freedom to choose one's identity affiliations is the antidote to divisive extremism. Stitched together from lectures, the book is dry and repetitive. While Sen's defense of humane pluralism against narrow-minded communalism is laudable, he never really elucidates the social psychology that translates group identity into violence.