“Your life must be an open city, with all sorts of ways to wander in.”

“After that, the book will fade, the way all books fade in your mind. But I hope you will remember this:A man walking fast down a dark lonely street. Quick steps and hard breathing, all wonder and need. A bell above a door and the tinkle it makes. A clerk and a ladder and warm golden light, and then: the right book exactly, at exactly the right time.”

“... nothing lasts long. We all come to life and gather allies and build empires and die, all in a single moment - maybe a single pulse of some giant processor somewhere.”

“When you read a book, the story definitely happens inside your head. When you listen, it seems to happen in a little cloud all around it, like a fuzzy knit cap pulled down over your eyes.”

“Are there sexual fetishes that involve books? There must be. I try not to imagine how they might work.”

“I've never listened to an audiobook before, and I have to say it's a totally different experience. When you read a book, the story definitely takes place in your head. When you listen, it seems to happen in a little cloud all around it, like a fuzzy knit cap pulled down over your eyes”

“Neel cuts in: "Where'd you grow up?""Palo Alto," she says. From there to Stanford to Google: for a girl obsessed with the outer limits of human potential, Kat has stayed pretty close to home. Neel nods knowingly. "The suburban mind cannot comprehend the emergent complexity of a New York sidewalk.""I don't know about that," Kat says, narrowing her eyes. "I'm pretty good with complexity.""See, I know what you're thinking," Neel says, shaking his head."You're thinking it's just an agent-based simulation, and everybody out here follows a pretty simple set of rules"-- Kat is nodding--"and if you can figure out those rules, you can model it. You can simulate the street, then the neighborhood, then the whole city. Right?""Exactly. I mean, sure, I don't know what the rules are yet, but I could experiment and figure them out, and then it would be trivial--" "Wrong," Neel says, honking like a game-show buzzer. "You can't do it. Even if you know the rules-- and by the way, there are no rules--but even if there were, you can't model it. You know why?"My best friend and my girlfriend are sparring over simulations. I can only sit back and listen. Kat frowns. "Why?""You don't have enough memory.""Oh, come on--""Nope. You could never hold it all in memory. No computer's big enough. Not even your what's-it-called--""The Big Box.""That's the one. It's not big enough. This box--" Neel stretches out his hands, encompasses the sidewalk, the park, the streets beyond--"is bigger."The snaking crowd surges forward.”