In November 1532, a group of 168 Spaniards seized the Inca emperor Atahuallpa in the town of Cajamarca, in the northern Peruvian highlands. Their act, quickly taken as a symbol of the conquest of a vast empire, brought them unprecedented rewards in gold and silver; it made them celebrities, gave them first choice of positions of honor and power in the new Peru of the Spaniards, and opened up the possibility of a splendid life at home in Spain, if they so desired. Thus they became men of consequence, at the epicenter of a swift and irrevocable transformation of the Andean region. Yet before...