What is technical democracy? And why does it matter for urban studies? As an introduction to this special feature, we address these questions by reflecting on To Our Friends, the 2014 manifesto of the Invisible Committee. We engage in particular its provocative diagnosis of the current situation: power no longer resides in the modern institutions of representative democracy and the market economy; instead, power has become a matter of logistics, infrastructures and expertise. This diagnosis, we suggest, brings into view the challenge of technical democracy, that is, the democratization of techno-scientific expertise and the instauration of forms of lasting collaboration among experts and laypeople. Urban politics, we claim, increasingly turns around socio-technical controversies and it is in terms of the politics of expertise that we should analyse and engage it. Building on Science and Technology Studies (STS), we conclude by pointing to four key conceptual dimensions of technical democracy—shared uncertainty, material politics, collective experimentation and fragile democratization—and provide examples taken from the papers included in this special feature.