Henry D. Thoreau's main work is not Walden or Civil Disobedience, but his journal, which he began at the age of 20 and continued until just a few days before his death in 1861. In it, he recorded observations that are among the most significant depictions of nature in world literature, as well as thoughts and reflections that reveal him as a distinctly independent philosophical thinker. Through reading it, it becomes clear that nature and politics, as well as solitude and the desire for social change, form a unity. Silence, independence, anti-materialism, poverty, anti-prudery, asceticism, self-discipline, and mystical searching are, alongside overwhelmingly precise and simultaneously poetic descriptions of life, nature, and both large and small living beings, the defining themes of this work. This extensive journal has influenced generations of artists and writers in America.