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SCIENCE fiction author William Gibson famously described cyberspace as a shared hallucination. Most people struggle to imagine what the internet’s physical structure looks like, but in Tubes, Andrew Blum sets out to find it. His first task is to disentangle our familiar, if not strictly accurate, conceptions about the internet from its actual cables, boxes and routers.

One such notion is the idea that the internet finds a route around censorship. This is true of the metaphorical overlay – take down a website and it can pop up elsewhere in an instant. But when it comes to the physical processes that prop up the metaphor, there is no going around them, as the grandmother who accidentally cut off Armenia by slicing through a cable buried in her garden showed.

In reality, every bit of information sent between New York and London – every email, Facebook status update, financial transaction and bid on an eBay teapot – makes its way through the same thin 4300-kilometre-long garden hose that submerges in Long Island and surfaces in Penzance. This marvellous shared hallucination is built on a series of tubes.

Tying the backstory and issues of the internet to its physical manifestations makes hard-to-grasp concepts easy to understand, even obvious. The history, in particular, is one of the best and most memorable I have ever read. And it is a satisfying postmodern quest, too: when Blum finds the centre of the internet, he is nonplussed to find something as unremarkable as a router.