Eugene Onegin by Alexander Pushkin (1833)

At her window past midnight, a country girl pours her whole heart onto the page to a man she has met once, certain she will love him forever. Tatyana's letter is the most famous declaration in Russian literature, and the cruelty of _Eugene Onegin_ is what comes after: the bored dandy reads it, and turns her down with chilly kindness. Pushkin wrote the whole novel in sonnet-like stanzas of his own invention, so the verse keeps dancing, witty and offhand, even as it walks toward a senseless duel between two friends. Tatyana grows up; Onegin learns, too late, exactly what he refused. The genius is the symmetry: two letters across the years, the same two people, everything between them reversed. Few books have made regret this elegant, or shown so plainly how a life can be ruined by the pose of having seen through everything.