For an often indecipherable book with openly revolutionary aspirations, Hardt and Negri's Empire has received an astonishing degree of mainstream, as well as radical, attention. This in itself suggests the need for a serious investigation of Empire's content, but our interest does not lie in identifying this book as a curious cultural artefact. Empire is ultimately an important book because serious engagement with the contradictory richness of its ideas on the nature of empire, capitalism and resistance in our time, can help advance the 'liberatory' project that we share with Hardt and Negri. Only the most ungenerous of reviewers could fail to admire the ambitious scope of their attempt to integrate history, philosophy, sociology, culture, and economics with a politics from below. And, yet, the end result is a most frustrating book: full of promise but also of inconsistencies, self-contradictions, flights of exaggeration, and gaps in logic.