Funded by the Economic and Social Research Council (ESRC) and the South Africa National Research Foundation (NRF), Security at the Margins (SeaM) was a three-year collaboration that brought together the University of the Witwatersrand, the University of Edinburgh, local government, and civil society partners to better understand and respond to marginality in urban South Africa, Kenya, and the United Kingdom. The hope was to create the foundations for a long-lasting, international, inter-institutional partnership. This publication features research conducted during the SeaM project and includes reflections by practitioners and research colleagues working in similar areas.