Mine’s The Unabridged Journals of Sylvia Plath. Thick books never stopped me from reading nonstop before, but there are entries in the book that just has me stopping and taking time to mull things over.
Also, sharing this excerpt: “Not to be sentimental, as I sound, but why the hell are we conditioned into the smooth strawberry-and-cream Mother-Goose-world, Alice-in-Wonderland fable, only to be broken on the wheel as we grow older and become aware of ourselves as individuals with a dull responsibility in life?”
Gulag archipelago, it’s really good but I have been known to read 1000 page novels in day, all 3 volumes of this one took me 6 months. It’s a heavy read and you basically need to be on Google the whole time to keep up with the slang in it.