If the story of the conquest of the Incas is little known, even less well understood is the legacy that the Inca empire bequeathed the world. From Peru came the potato, which transformed the agricultural economies of Europe, from Ireland to Russia. The gold taken from the Inca empire by the Spanish and melted into ingots before trans-shipment to Spain paid for the armaments that prevented the Ottoman empire from overrunning Europe. The stupendous quantity of silver taken by the conquistadores from a single mountain in Postosi, Bolivia - and extracted by means of the pitiless use of Indian slave labour - made Europe and Asia liquid in money for the first time in history and financed the foundations of our modern economic world. And as if this were not enough, the Incas preserved, right up to the very threshold of the modern world - in whose creation their demise played such a crucial part - a way of thinking about the cosmos that at one time belonged to all of us, and which the Incas, now, have given back to us.