It is as true to say that Americans and Europeans are united by an ocean as divided by one. And while horsemen are often considered insular, their transatlantic engagement--fluctuating but perennial--means that they always have things to learn from one another. In recent times, contrary to European prejudice, it is the Americans who have been more willing to leave their comfort zone. Whereas not even Coolmore have lately been rolling the dice on the dirt at the Breeders' Cup, American raiders have increasingly enriched the pageant of Royal Ascot. And...