As world economies have become increasingly globalised, cities have undergone dramatic transformations, resulting in a new economic order with minimal localisable terrain; simultaneously, there has been enormous urban growth. These developments have had significant implications for natural environments and the lived physical/social environments of human beings. Philip Reeve's Hungry Cities [Mortal Engines] Chronicles explores the complex relationships between global economics, urbanisation and environmentalism by mapping these onto two utopian models: utopianisms of process; and spatial utopias. This paper examines the paradigmatic function of these two models within Reeve's tetralogy, focusing on the implications of each for thinking through interrelationships between capitalism, environmentalism and urbanisation. Economic, urban and natural spaces are envisaged throughout the Chronicles as ‘cyborgian’, and, hence, capable of adaptation but also apt to stagnation. They thus embody both threat and promise: they warn of an annihilation of the human spirit, but also remember the humanity's heterogeneity. Reeve directly invokes these diverse possibilities in his depiction of warring cities, envisaging a distinctly posthuman world, but one within which human relationships, alongside a sense of the importance of history and narrative, offer certainty and the possibility at least for the construction of urban communities grounded on utopian ideals.