The IAS research theme Investigating Infrastructures explores novel ways of researching infrastructures. Over the past decade, there has been an enormous increase in scholarly interest in infrastructures as an object of research and a methodological approach. The ‘infrastructural turn’ in the study of borders, climate, ecology, energy, finance, the military, migration, mobility, security, and transport has introduced multiple novel concepts and approaches. With ‘Investigating Infrastructures’, we organise workshops and seminars and build a community of researchers to further research, policymaking and public debate.