To know Russia, you really have to understand 1837. The assertion might seem strange. Even among historians of Russia, it is likely to produce head-scratching rather than nods of knowing approval. Most would point to other years—1613 and the birth of the Romanov dynasty; 1861 and the end of Russian serfdom; 1917 and the Bolshevik seizure of power—as more consequential. But in fact 1837 was pivotal for the country’s entry into the modern age and for defining many of Russia’s core attributes. Russia is what it is today, in no small measure, because of 1837.