If you read the book -- and it's definitely worth it -- I cannot strongly enough recommend that you read through the Crooked Timber online symposium about it. Graeber has written a fascinating book, but his reach may have exceeded his grasp on several important fronts:
I particularly recommend The World Economy is Not A Tribute System (http://crookedtimber.org/2012/02/22/the-world-economy-is-not-a-tribute-system/) and Too Big To Fail: the First 5000 Years (http://crookedtimber.org/2012/02/25/too-big-to-fail-the-first-5000-years/).
no subject
http://crookedtimber.org/2012/02/28/seminar-on-david-graebers-debt-admin-notice/
I particularly recommend The World Economy is Not A Tribute System (http://crookedtimber.org/2012/02/22/the-world-economy-is-not-a-tribute-system/) and Too Big To Fail: the First 5000 Years (http://crookedtimber.org/2012/02/25/too-big-to-fail-the-first-5000-years/).