This open access book Design Participation presents doable and demonstrated ways by which design can become a major contributor to social and environmental change. This entails a shift from seeking to define solutions to opening spaces in which others-activists, entrepreneurs, civil servants, neighborhood communities, politicians (and so on) -can effectively elaborate on and find (re)solutions to the matters they are facing. It is now time to pursue design participation for real: in earnest, skillfully and for real problems. Building on a twenty-year research program, Design Participation shows that participation matters and provides an encompassing resource for understanding the matters of participation: how to think, reflect, plan and work in design participation in different settings and for different issues.