This is the will be the easiest part of the book to digest. There is little technical discussion in it and Wolfram describes what led him to write the Book. He also talks about why he thinks the Book is so important. Writing it was a fifteen year-long journey into the land of the midnight oil.
He estimates the Book to weigh in at 250,000 words. The "notes" don't even kick in until page 849.
Jumping to the back, we see a section called "General Notes." Here are the common terms("website", "writing style", "dates") on which he elaborates. From what I can tell, he likes to start sentences with conjunctions. And he does it often. But not always.
Wolfram doesn't shy away from making big claims. On page 850 he says:"The vast results in this book have never appeared in any form before." He's also interested in the educational aspect of the Book: he wants people to use what they've learned.
Okay, just what the heck is this book about? Cellular Automata. Huh? Let me see if I can explain it a little better: remember chaos theroy? Fractals? That damn butterfly flapping its wings in the jungle that causes all the hurricanes? These are steps in the right direction, but Wolfram wants The Big Question to cover everything.
Take some tiles. Some black, some white. Cover the mall floor in Washington D.C. with them. But first, devise a rule as to what tile can sit next the next one. Follow that rule carefully when you lay down the tiles. Now, when it's all done, walk to the top of the Washington monument and look down at what you've did. What do you see? Is it the eye of God looking back at you?
At least this is what I think the Book is about. By the time I get to the end I should have a complete and total understanding of what Wolfram is trying to say. Then I may have a better description.