Early in the 19th century, imperial Russia fed much of Europe through the booming port of Odessa in Ukraine. But following the U.S. Civil War, tons of American wheat began to flood across the Atlantic, and food prices plummeted. This cheap foreign grain spurred the rise of Germany and Italy, the decline of the Habsburgs and the Ottomans, and even the outbreak of the First World War and the Russian Revolution. To understand the rise and fall of empires, we must follow the paths traveled by grain, and here Scott Reynolds Nelson reveals how the struggle to dominate these routes transformed the balance of world power.