It's a history of the origins of Western ethnology in the Jesuit enterprise of evangelizing the Americas, which the author never deigns to call cultural and linguistic genocide (Pagden gets in a "linguistic imperialism" on p.182), but the full extent of which is still being documented, e.g. the mass child graves presently being exhumed in the old Canadian Indian residential school system.

The debates among Spanish intellectuals about the nature of the Americans they found themselves ruling over sound a lot like any contemporary debate among Euro-American intellectuals about whom to bomb next. In place of spurious allegations of cannibalism you can just insert a complaint that the enemy is using 'human shields' or 'developing weapons of mass destruction'. Francisco de Vitoria even argued that the Spanish had a right to treat the Americans like serfs because the Americans violated the natural law -- 'love thy neighbor' -- by being inhospitable to their new neighbors, who were merely extending a friendly greeting when they kept forcing the existing tenants onto encomiendas. It strikes me as roughly analogous to the contemporary policy: 'They hate us for our freedom, so we'll occupy them until they love us.' But then why would I expect that logic to ever change? Who will liberate empire from the timelessness of its own inverted rationalizations?

The writing is really quite good and frequently engaging, but I'm going to dock a star for the subject matter's endless turbidity in the waves of this or that author's application of Aristotelian logic to their categorizations of slaves and barbarians. It might be a better book if those tedious and repetitive arguments had been pulled out into a separate chapter for comparison, to see what meaning can be teased out of the thinkers' (often seemingly trivial) differences.