The world of Anathem is so different from our world that an average writer would need to devote the first 10 chapters to description and a historical summary. Stephenson manages to focus on the familiar and then explain the differences as they become relevant. I never needed to just keep reading in the hopes that things would start to make sense eventually. I didn't wind up partway through the book needing to start over because I finally had enough information for the first chapter to make sense. He got the flow of story and flow of information absolutely perfect. He also managed to make a very alien world and culture feel extremely comfortable.
Given the awesomeness of the setting, this would be a good book even if the story itself wasn't all that great, but that isn't the case at all. The story is fascinating and the plot unfolds at just the right pace to keep you riveted without being overwhelmed. I'm totally in love with the Socratic dialogue all the way through, the style of communication that's used to teach new ideas by leading you through the entire thought process so that you get to make the discovery yourself (or get totally planed by the person leading the dialogue). The dictionary definitions starting each new segment - the fact that you've often encountered the word before with just enough context to make sense of it, but are now getting the full definition and derivation of the word with all of its different nuances - were totally amazing. The language is almost an evolving character in the story. Words can have different meanings depending on who is using them (which could wind up being totally confusing, but Stephenson manages the context so well that it doesn't).
I do need to read this again. I didn't pay nearly enough attention to the whole Rhetor/Incanter history as I wish I had. It didn't feel quite as relevant to the story as it wound up being. I really thought the book was going to be very different than it actually was. I was surprised by the turn things took halfway through, and yet it was a good surprise rather than a bad one. Surprise is a great thing coming at the very end of a mystery, but coming halfway through a book like this, turning the story in a completely unexpected direction - could be very upsetting if done wrong.
This was a fabulous book. It is only overwhelming because it is so long, but it isn't at all hard to read - the plot and the characters keep things moving along quite nicely.