Colin Marshall sits down in Winchester, England with PD Smith, author of books on science, literature, superweapons, and, most recently, City: A Guidebook for the Urban Age. They discuss whether London has all the elements of the archetypally ideal city; the essential quality of "a place where you meet strangers"; the need to avoid writing only about buildings; the recent moment when half the world's population found itself living in cities; the factors that have made city life more possible today than ever before; what on Earth Prince Charles talks about when he talks about architecture and urbanism; the enduring impulse to knock cities down and start them over; the un-knocked-down city as a palimpsest-like store of knowledge, perhaps with its own "latent consciousness"; Tokyo and the metaphor of city as body; whether, in experiencing cities or writing about them, to focus on one element at a time or to try to take them whole; what Germans get right about city-building; when and where Starbucks starts to seem like the most foreign place you could go; the globe-spanning "cities" of the airport, the high street, or any other non-place; what it takes to make London strange again; the detective as a quintessentially urban figure exhibiting a mastery of his sensationalistically grim, dark, troubled environment; and the challenge any interesting city issues its resident: "Figure out how to live in me."