Our modern-day cities might seem to represent our separation from the natural world. In fact, as Ben Wilson reveals in this captivating re-examination of urban landscapes around the world, nature has always been at the heart of the city.Wilson explores the wild side of cities, past, present and future: the middens, abandoned sites and strips of land alongside railway lines. For much of history, wild patches in cities provided essential food, fuel, medicine and places of recreation and escape for city-dwellers, and the dividing line between city and countryside was blurred. Even our post-industrial cities are much wilder places that we might imagine, with booming animal and plant populations, if we know where to look.In today's urbanised planet, natural forces - be they floods, storms, droughts or pandemics - look set to determine the future of our cities. In a time of climate crisis, cities that once built walls and towers to defend against attack; now they have to become greener to protect themselves from external threats. Our future - and that of the planet - will be made in the city. Only by looking deep in to the past, examining the present and casting an eye to the future can we really begin to understand the bountiful potential and wonder of our extraordinary urban ecosystems.