Second this. Because it's set in a parallel universe very similar to our own (yet with striking differences), Anathem is heavy going for the first hundred pages or so, mainly because the language and cultural assumptions are unfamiliar. There are lots of made-up words that sound tantalisingly like English, but are not; the title of the book itself is one such word, a sort of amalgam of "anathema", "analemma", and "anthem".
But it is definitely worth the effort. It's the only Stephenson novel I've ever felt compelled to reread for the sheer joy of it.