From 1837 to 1861, Thoreau kept a Journal that began as a conventional record of ideas, grew into a writer's notebook, and eventually became the principal imaginative work of his career. The source of much of his published writing, the Journal is also a record of both his interior life and his monumental studies of the natural history of his native Concord, Massachusetts. In contrast to earlier editions, the "Princeton Edition" reproduces the Journal in its original and complete form, in a reading text that is free of editorial interpolations but keyed to a comprehensive scholarly apparatus. "Journal 6" comprises a single manuscript notebook of nearly five hundred pages that Thoreau filled between March 9 and August 18, 1853. During this period, Thoreau divided his energies among his increasingly professional studies as a naturalist in Concord, the revision of his Walden manuscript, and surveying, which provided him a living and established him more securely as a contributing member of the Concord community. Thoreau's writing and his understanding of natural history were enriched by surveying, which gave him the opportunity to regularly observe seasonal occurrences and other natural events in and around Concord. Thoreau recorded these observations in his Journal, making both literary and scientific use of them. Substantial passages from "Journal 6" were incorporated into the sixth draft of Walden, and its observations formed the basis for later compilations of field ecology. They are made available here, along with Journal entries, completely unrevised. This volume will delight all custodians of literary and natural history and be an essential addition to the libraries of all Thoreau devotees.