May I offer two? Isaac Newton's Philosophiæ Naturalis Principia Mathematica (in english translation) -- in a transatlantic flight I managed 7 pages. Herman Melville's Moby-Dick -- I get about halfway then my head spins too much trying to keep up. with the subtleties. I did get all the way through Catch 22. Once. A long time ago. A newly purchased copy is looking at me now but I'm avoiding its gaze.