Cities are exploiting information technology to transform themselves to compete in a global knowledge based, service led economy. The history of large technical systems (LTS) deployments explains the impact of telegraph, telephony, electrical networks and other technologies on cities in the 19* and early 20' century and how some fared better than others in terms of the socio-economic outcomes. In this thesis I examine how the LTS model applies to digital infrastructure including broadband, municipal wireless and related services - how are cities in the 21" century using or planning to use these technologies; what are their motivations and expectation; what has been the contribution to date, and what are the factors affecting the outcomes? The LTS model provided a useful framework as it focuses on the technical system within a larger socio-economic and political context. My research focuses on the city as the unit of analysis whereas the LTS model focuses on the technical system, although Hughes's model contextualises LTS for the city (Hughes, 1983). My research seeks to extend the LTS model by proposing an increased role for organisations versus individual agency. It shows how those organisations form into actor networks that interact and influence the outcome of the system at the level of the city. Finally, I propose the Complex City System (CCS) framework as an extension to the LTS model. The CCS framework integrates the role of these actor networks, as well the socio-economic, technical and spatial factors at work within a city, and shows how these both shape the technical system and its socio-economic contribution.