A Week on the Concord and Merrimack Rivers — Thoreau's first book, published at his own expense in 1849 — the record of a two-week boat journey he made with his brother John in 1839, written after John's death and threaded with long digressions on friendship, Eastern and Christian scripture, history, and poetry.
Cape Cod — Henry David Thoreau's account of his walking trips along the outer shore of Cape Cod between 1849 and 1855, published posthumously in 1865 — ten chapters that open among the coffins of the wrecked brig St. John at Cohasset and end at Provincetown, with Clifton Johnson's introduction to the 1908 illustrated edition.
Civil Disobedience — Thoreau's 1849 argument that the individual conscience must supersede unjust law — the foundational text of nonviolent resistance.
The Maine Woods — Thoreau's three journeys into the Maine wilderness between 1846 and 1857 — the Ktaadn ascent, the moose hunt at Chesuncook, and the Allegash canoe voyage with the Penobscot guide Joe Polis — collected posthumously in 1864, with his appendices of trees, plants, birds, outfit, and Indian words.
Walden — Thoreau's 1854 account of two years living deliberately at Walden Pond — the foundational American text of voluntary simplicity, nature, and awakened consciousness.