This special issue, instead of questioning what effect peacebuilding interventions have on post-conflict societies, analyses what the ground of intervention does to peacebuilders. It demonstrates that everyday interactions on the ground shape the interveners and even the scope of their missions. We delineate how a political sociology approach might break away from binaries ('internationals/locals') and, instead, illuminate processes (of internationalization and localization). We intend to offer a political sociology of the 'intervention encounter', that is, to scrutinize the everyday interactions among peacebuilders and between peacebuilders and domestic actors, and to investigate effects of the ground on peacebuilding organizations, doctrines and decision-making processes, as well as on peacebuilders' trajectories, positions, professional practices and representations. In fine, we explore how peacebuilders' relations to the ground structure the socio-professional field of peacebuilding.