<p>Strategically situated at the gateway to the Mississippi River yet standing atop a former swamp, New Orleans was from the first what geographer Peirce Lewis called an &quot;impossible but inevitable city.&quot; How New Orleans came to be, taking shape between the mutual and often contradictory forces of nature and urban development, is the subject of An Unnatural Metropolis. Craig E. Colten traces engineered modifications to New Orleans's natural environment from 1800 to 2000 and demonstrates that, though all cities must contend with their physical settings, New Orleans may be the city most dependent on human-induced transformations of its precarious site. In a new preface, Colten shows how Hurricane Katrina exemplifies the inability of human artifice to exclude nature from cities and he urges city planners to keep the environment in mind as they contemplate New Orleans's future. Urban geographers frequently have portrayed cities as the antithesis of nature, but in An Unnatural Metropolis, Colten introduces a critical environmental perspective to the history of urban areas. His amply illustrated work offers an in-depth look at a city and society uniquely shaped by the natural forces it has sought to harness.</p>