The anthropologist David Graeber has a strong claim to being the house theorist of Occupy Wall Street. A veteran of the antiglobalization uprisings in Seattle and Genoa, he helped orchestrate the first ''General Assembly'' in New York this summer, and has since become one of the movement's most outspoken defenders. For him, the encampments in cities across the country prefigure the kind of anti-hierarchical, stateless society that ought to be our future. In a recent opinion article in The Guardian of London, Graeber proclaimed OWS ''the opening salvo in a wave of negotiations over the dissolution of the American Empire.'' For a movement that has attracted an array of political sympathies, his voice reminds us that at its organizational core, Occupy Wall Street cleaves to anarchist principles. But Graeber's most important contribution to the movement may owe less to his activism as an anarchist than to his background as an anthropologist. His recent book DEBT: The First 5,000 Years (Melville House, $32) reads like a lengthy field report on the state of our economic and moral disrepair. In the best tradition of anthropology, Graeber treats debt ceilings, subprime mortgages and credit default swaps as if they were the exotic practices of some self-destructive tribe. Written in a brash, engaging style, the book is also a philosophical inquiry into the nature of debt -- where it came from and how it evolved. Graeber's claim is that the past 400 years of Western history represent a grievous departure from how human societies have traditionally thought about our obligations to one another. What makes the work more than a screed is its intricate examination of societies from ancient Mesopotamia to 1990s Madagascar, and thinkers ranging from Rabelais to Nietzsche -- and to George W. Bush's brother Neil. [ABSTRACT FROM PUBLISHER]