"In 1900, just 10% of the world’s population lived in cities. Today more than half of humanity are city dwellers, and with each day that passes this proportion rises inexorably. We are living in a truly urban age. Global cities have become the engines of the modern economy and decisions made in cities touch the lives of every person on the planet. The challenges faced by the world today, from climate change to poverty and inequality, are concentrated in cities and often played out on their streets, in demonstrations and riots. The city has become the theatre of our anxieties as well as our hopes."
My review of Living in the Endless City, edited by Ricky Burdett and Deyan Sudjic, and The New Blackwell Companion to the City, edited by Gary Bridge and Sophie Watson, is in the current Times Literary Supplement (February 10, 2012, p 24). I have posted a somewhat longer version of the published review here.