This book documents the methodology and findings from an Architecture Sans Frontières (ASF-UK) action research workshop, Change by Design, undertaken in Nairobi, Kenya, which explored the opportunities and limitations of community-led participatory design which directly engages slum dwellers in planning slum upgrading projects. Through concurrent investigations at the ˜macro' institutional scale, the ˜meso' neighbourhood scale, and the ˜micro' dwelling scale, the findings highlight that undertaking participatory design at these three scales is a proactive way to facilitate negotiations, highlight diversity and reach consensus. Central to the innovative approach is a focus on the degree to which it can not only build an improved physical environment but also recognise the social production of space; empower slum dwellers to be active agents of change; and build socially, economically, and environmentally sustainable communities.