In 2008 for the first time the majority of the planet's inhabitants lived in cities and towns. Becoming globally urban has been one of mankind's greatest collective achievements over time, and raises many questions. How did global city systems evolve and interact in the past? How have historic urban patterns impacted on those of the contemporary world? And what were the key drivers in the roller-coaster of urban change over the millennia - market forces such as trade and industry, rulers and ...