ARCH (Action Research Collective for Hospitality) was created in January 2019, in the continuity of the work carried out at Metrolab Brussels on the theme of “urban inclusion” with the intention of pursuing observations, analyses and practical considerations on the qualities of hospitality in Brussels’ urban spaces, mainly where this issue seemed most pressing: the Maximilian Park, the North Station, the Northern Quarter (on whose periphery is located the Metrolab studio). ARCH has gradually been built up through the voluntary involvement of many researchers (academics or not) and practitioners with diverse backgrounds (sociologists, architects, urban planners, artists, activists, anthropologists) in a collective action research project aiming to promote urban hospitality in Brussels, which is a metropolis either crossed and impacted by migration movements. Urban hospitality is understood as the ability of an urban environment to open up and welcome newcomers who come forward ; here more precisely, people in migratory situations occupying different places in the Northern Quarter. Witnessing the deplorable conditions of their extreme reception, vulnerability and distress, ARCH members have come together to highlight their situation and call on the people of Brussels (particularly public authorities, administrations and urban affairs professionals) about our common duty of hospitality and humanity. The research was developed over a short period of time, in close collaboration with the Citizen’s Platform – which welcomes hundreds of people every day among the 800 migrants and refugees present in this part of the city. The Platform co-defined the lines of the survey with ARCH members according to some of the needs and problems it faced on a daily basis, and contributed to the implementation and progress of research activities, as well as the production of results. We conducted this inquiry using a combination of methods based on collective exploration of the neighbourhood, ethnographic observation and mapping of places of occupation and reception, participation in the work and activities of the Platform, organisation of focus groups, conducting interviews, etc. Today, we’re publishing the results of this collective research – already exhibited, presented and discussed for the first time at a symposium held in June 2019 – in order to share the knowledge produced with all those interested in this issue, and to challenge the politicians on the hospitality issues facing the Northern Quarter. The Brussels government has recently made available a significant amount of funding to enable the Humanitarian Hub and the Porte d’Ulysse shelter to continue their activities over the next two years, demonstrating in the same way its attention to the challenges of reception and its commitment to a more decent migration policy. However, the problems arising from the presence of migrants in the Northern Quarter and its public spaces remain poorly considered in the field of urban policies. By adopting a socio-spatial perspective on these issues, this book invites us to extend this commitment towards a policy of urban hospitality.