

Ovenden uses Beck to map the world: Yekaterinburg is at the end of the Victoria Line, New York busted down from world hub to penultimate stop on the Central Line, Pyongyang accorded more significance than Beijing.

Indeed, the inside cover of Garfield's book is illustrated by the transport writer Mark Ovenden's riff on Harry Beck's iconic London tube map. But then maps, as Garfield notes throughout the book, are as much about imagination as power, inspirations as much as guides.

The escarpment between today's Hampstead and Highgate figures in that novel as the Isle of Ham, while Garfield's house and surrounding streets have been washed away forever. On the inside cover of The Book of Dave by Garfield's schoolfriend Will Self, there is a map depicting a flooded, post-apocalyptic London. Pearsall's A to Z makes me think of another map. Striking, isn't it, that it took a woman to unravel London's labyrinth, to wrest its topographical mysteries from mostly male London cabbies whose obscure rites culminate in something called "the knowledge"? Pearsall's is one of the stories in Garfield's lovely ramble through space-time from cartography's birthplace, the great library of Alexandria, to the Californian HQ of Google Maps.
