The September 11 attacks in New York and Washington have forced Americans to confront the fact that to live or work in a large city is to be at greater risk of large-scale terrorism. What do these risks, and the public perception of them, imply for cities in general and the future of New York...

In this letter I summarise the main results and contributions from my Ph.D. thesis on concentration of resources and economic development. The empirical analysis performed in the thesis, and summarised here, focuses on two mayor world trends in modern economic development, namely increasing...