In the aftermath of the horrific trench warfare of the First World War, the poppy -- sprouting across the killing fields of France and Belgium, then immortalized in John McCrae's moving poem -- became a worldwide icon. Yet the poppy has a longer history: as the tell-tale sign of human cultivation of the land, of the ravages of war, and of the desire to escape the earthly realm through Romantic opium dreams or the grim reality of morphine drips. This is a story spanning 3,000 summers, from the Ancient Egyptian fights over prized medicinal potions to the addicted veterans turning home from the...