Triumph of the City, By Edward Glaeser

Many see the city as a burden on humankind, and the globe's growing urbanisation as an environmental and social threat. For others, cities are places of opportunity. And people are voting with their feet because half the world's population now lives in cities. But this huge phenomenon of urbanisation has received very little modern economic analysis.

Insofar as it has been studied at all, the emphasis has been on the problems of urbanisation, particularly in the emerging economies, rather than the opportunities. So, it is truly refreshing that Ed Glaeser, Professor of Economics at Harvard, should give us this celebration of the boom in cities, explaining, as the subtitle of the book says, "how our greatest invention makes us richer, smarter, greener, healthier and happier".

Really? Richer, most people would accept, at least in terms of GDP generated. People living in cities generally are better educated, with most of the great universities of the world located in cities. Healthier, you can measure, and it is a fact that longevity is highest in the greatest urban agglomeration in the world, Tokyo.

Happier, might seem tougher to substantiate. But one of the most useful concepts in economics is "revealed preference" which, applied simply, means that you look at what people choose to do and start with the presumption that this is what makes them happier and that therefore you need to be cautious about any policy that resists the choices they make. People move to cities, that is, because they think they will have a better life.

And greener, might seem the hardest to prove of all. Here, Glaeser argues that the energy footprint of people in traditional cities (though not the sprawls of US ones) is much lower than that of people of similar income in the country.

In a thrilling ride around the world's great cities, he looks at why some cities decline (such as Detroit and Liverpool) and what might be done about it; and why others grow (Bangalore, Sing-apore, etc) and how policy has helped that process. Glaeser throws out some squibs, for example: what is good about slums; what's so great about skyscrapers; and why has sprawl spread? He has a message for London, which he sees as a great luxury resort, praising the vision of Ken Livingstone – interesting that – and calling for it to be allowed to grow upwards. And he suggests that our modern suburban spread will be seen as an historical aberration: density will be back.