Walden, by Henry David Thoreau (1854)
Walden is nonfiction, a combination of memoir, philosophy, and nature writing.
(1) Throreau is an intertextual writer. He uses wordplay, puns, etymologies, ancient Greek words, in-text quotations, bible allusions, allusions to the mythologies of Greece and India, allusions to Confucius. All this makes Walden a dense, hard-to-read text.
(2) Along these lines, Thoreau openly discusses his love of reading. But he also talks about how he sets aside reading for working with his hands. These two activities need to be in balance, which makes a lot of sense to me: it's hard to focus on reading all day.
(3) Sometimes Thoreau makes comparisons, using just one word, between people and nature (e.g. potato-rot and brain-rot).
(4) Thoreau wonders about how the Walden pond seems foreign, or reminds him of foreign parts, especially in winter. This happens in many passages across the book. One of the main themes of the book is Thoreau's idea that travel to foreign places isn't as good as "traveling" (fully exploring) within one's own environment and one's own mind.
(5) Thoreau understates his dependence on other people to live; he imagines that he can live using only his own skills. He also insults women and older people, claiming that mere experience of life doesn't make a person wise.