What is the potential of new technologies to generate, in a decentralized and participatory way, reliable spatial information to support urban and social development? More precisely, what is the potential of new technologies to enhance citizen participation in decision-making processes? These were the main questions brought up during the meeting Mapping Techniques and Citizenship, held in São Paulo in November 2018. The present book gathers contributions by experts from different disciplines, that were presented during the meeting, which contributed to the debate on cartography and citizen participation in the context of emerging countries’ metropolises marked by deep socio-spatial fragmentations and by divergent political agendas regarding urban development.