Alfred Döblin’s epic novel Berlin Alexanderplatz (1929) is widely considered to be one of the twentieth century’s greatest city narratives. This pseudo-religious story of a disturbed ex-con’s epiphany and redemption has been hailed in recent years as a proto-postmodern tribute to Weimar Berlin. But my chapter aims to show that we can only do full justice to Döblin’s masterpiece by reading it against the backdrop of his biologically inflected aesthetics and anthropology. The first part examines the inexorable collapse of Franz Biberkopf ’s attempts to restore some kind of sovereign control over his life in the city: both his body and his environment. But in the face of his repeated defeats, I then turn to read the traces of ‘creaturely life’ within the text. These relate to uncanny points of crossover and hybridity between man and animal, which may, in turn, shine unexpected new light on the very ‘nature’ of human identity at the heart of the modern city.