'TUBES' from H10

plug in a socket. Again and again we share Blum's surprise and pleasure in learning that, rather than being "everywhere," the Internet has hookups in very specific places. Indeed, in his attempt to peek behind the curtain, Blum sometimes gets bogged down in the physical details, the plod from one place to another, and one wonders why he waits until the book's end to get to the good Google gossip.

Readers will appreciate the book's clear explanations of complicated processes, though some will enjoy it simply for Blum's sense of wonderment; if sheer magnitude is your thing, you won't be let down. At one point, Blum marvels at the amount of information traveling through the networking cables as he stands in a room looking at them, each one "represent[ing] up to ten gigabits of traffic per second - enough to transmit ten thousand family pictures per second."

But as he does by conjuring those snapshots that fill Facebook to bursting, Blum keeps circling back to the same basic idea, as touching as it is true: that the Internet, wherever it exists physically, is an extension of the human networks that were forged a long time ago.

Even the visionary Kleinrock was unable to see what the Internet would come to mean. "I thought it was going to be computers talking to computers or people talking to computers," he says. "That's not what it's about. It's about you and me talking."