I'd been looking forward to reading Ed Glaeser's book Triumph of the City, and haven't been disappointed. One of the most creative and rigorous of urban economists has long been publishing fascinating academic papers on cities and related issues such as the role of social norms in affecting economic outcomes. Those years-worth of research inform a book which is a real page turner.

The individual chapters cover different themes – such as the importance of skilled people for a city's economic success, the role of transport systems in shaping cities, slums and urban ghettos, the environmental footprint of urban life. Understanding what makes cities function – or not – is important because, he argues, cities are our future. More than half the world's population lives in cities, including the rapidly growing mega-cities in developing countries. “The enduring strength of cities reflects the profoundly social nature of humanity,” he writes. (p269) A Manhattanite born and bred, he clearly loves cities, despite having become a suburbanite in recent years. “What terrible bout of insanity induced me to choose deer ticks as neighbours instead of people?” (p166) However, thinking about the reasons for his own choice helped inform his suggestions about improving city life. After all, while cities have the people, variety, cultural activities, restaurants, choice, liveliness and other amenities, they also have congestion, pollution, expensive housing and other disamenities.

Some possibly surprising conclusions emerge from the analysis. Here are some of them:

1. People matter, not places – a thriving city needs skilled workers, who seek each other out and make each other more productive by example and by sharing ideas. Buildings don't make a city, as so many examples of failed construction programmes demonstrate. A classic mistake of urban planning is to think the buildings come before the people when in fact it's the other way round.

2. The better the municipal authorities make a city for poor people – with housing, transport, social programmes – the more poor people there will be. After all, nothing is worse than being poor in the countryside where there's nothing to do. People on low incomes move to the city for opportunity, and the more help a city offers, the more poor people will stay or arrive.

3. Preservation ultimately destroys a city. Forbidding changes puts the brakes on normal urban dynamism and will eventually turn a city into a playground for rich residents and tourists rather than a functioning economy. Some preservation is desirable – surely Jane Jacobs was right to campaign against a highway going through Washington Square – but too much disney-fies a place. Paris seems to have suffered this fate, beautiful as it is.

4. If cities can't grow up, they grow out. A successful city attracts more and more people who need somewhere to live. The density at which they live depends on how many new tall buildings are constructed. If planning restrictions mean high rise homes can't be built, housing prices will rise, while people on lower incomes will live far away and commute. Either that or move to Houston, or some suburb or smaller city where buildings sprawl.

5. Cities are better for the environment than the countryside. Collecting people together with shorter commutes reduces the amount of driving and increases walking and the use of public transport.

Ed Glaeser is an advocate of this type of densely-populated, walking (or public transportation based) city, with new buildings and a variety of uses. He argues against some of Jane Jacobs' specific conclusions in her classic The Death and Life of Great American Cities (especially about high rises) but is entirely in sympathy with her passion for the wealth and potential of urban life. He concludes that in time living in suburbs will prove ephemeral, not least because of the need to avoid long commutes by car. “Our culture, our prosperity and our freedom are all ultimately gifts of people living, working and thinking together – the ultimate triumph of the city.”

I agree. What's more, as an economist I very much enjoyed the rigour with which assertions made in the book are supported by evidence. Some bits of evidence are particularly delicious. For example, New Yorkers aged 25 to 34 are 75% less likely to die in a car accident than their equivalents nationwide – because when they're drunk they take the subway home instead of driving. The New York suicide rate for young people is 56% of the national average. I thought this might be because they're less bored, but this being the US it's because they are far less likely to have access to a gun with which to shoot themselves. But older New Yorkers are also much healthier than the national average. In contrast to the pre-industrial era, cities are places where people are more productive, happier and healthier.

There's all this and much more in Triumph of the City for any municipal policy maker, economist or urban flaneur.