Weighing in at just under one thousand pages and probably a pound and a half this book takes some concerted effort to get through. This effort is even more difficult given that Neal Stephenson has decided that the book takes place on a parallel earth complete with it's own lexicon. Keeping this straight in your head is non-trivial.
Aside from that, it's brilliant. Stephenson is probably one of the greatest authors writing today. I just wish he didn't know it so much and keep it down to Snow Crash levels.
http://www.amazon.com/Anathem-Neal-Stephenson/dp/0061474096/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1231185316&sr=8-1