Leo Hollis - who has written two books about London, where he lives - sees the city as a landscape of limitless possibility that may hold the key to our survival, since we are increasingly "an urban species".
He explains: "In 2007 the UN announced that for the first time in human history 50 per cent of the world's population now lives in cities. By 2050, it is projected that 75 per cent of the world's populations will live in cities."
When Hollis refers to this expanding urban population, he's not talking about the traditional cities of the West. Indeed, he spends much of the book discussing cities such as Shanghai, Singapore and Dubai, which operate according to a different model.
His thesis is that the city "is not a rational, ordered place but a complex space that has more in common with natural organisms such as beehives or ant colonies" - complexity theory, in other words, which means our cities are less inventions than entities, evolving from the ground up.
Unfortunately Hollis spends too little time in the street. His accounts of various cities skim over the question of what they feel like, what we call their quality of life.
"The divide between the ambitious dream and the evidence on the ground," Hollis writes of Mumbai, "became clear as soon as I left Bandra station … An elevated walkway - the skywalk - rose from the station concourse above the tracks and then continued to direct me along a lengthy covered pathway. From this height it soon became apparent that the walkway was not just avoiding the rail lines but also a squatters' colony that stood only a few yards across a rubbish heap from the busy tracks." Hollis gives a few details about this "no-man's land" of the city, but he never does get down in it, preferring to observe from above.
This becomes increasingly problematic as Cities are Good for You progresses, cycling through a checklist of urban issues: design, transportation, walkability, sustainability, inequity. Hollis is at his best when bringing in unexpected elements, such as the rise of cellphone banking in Africa or the use of social media to mobilise protest movements, to illustrate the connections by which we are now bound. The earth is becoming one vast urban matrix. Still, the unanswered question is what it means for the daily life of actual people on the street.