Introduction: land of the grass-ground river -- The making of Thoreau. Concord sons and daughters ; Higher learning from Concord to Harvard (1826-1837) ; Transcendental apprentice (1837-1841) ; "Not till we are lost" (1842-1844) -- The making of Walden. "Walden, is it you?" (1845-1847) ; A writer's life (1847-1849) ; From Concord to Cosmos: Thoreau's turn to science (1849-1851) ; The beauty of nature, the baseness of men (1852-1854) -- Successions. Walden-on-Main (1854-1857) ; Wild fruits (1857-1859) ; A constant new creation (1860-1862).