Reyner Banham’s Los Angeles: The Architecture of Four Ecologies was one of the first books I ever read on Los Angeles, and one of the first books I read about ecology. As a result, the concepts “Los Angeles” and “ecology” are irrevocably linked in my mind. But it’s an improbable pairing. Los Angeles is a city where the natural landscape is woven into the fabric of the city, but it is also our most intense site of the artificial. As Mike Davis has put it, Southern California is “Walden Pond on LSD.”