This book brings together fifty of today’s finest thinkers. They were asked to let their imaginations run free to advance new ideas on a wide range of social and political issues. They did so as friends, on the occasion of Philippe Van Parijs’s sixtieth birthday. Rather than restricting themselves to comments on his numerous writings, the authors engage with the topics on which he has focused his attention over the years, especially with the various dimensions of justice, its scope, and its demands. They discuss issues ranging from the fair distribution of marriage opportunities to the limits of argumentation in a democracy, the deep roots of inequality, the challenges to basic income and the requirements of linguistic justice. They provide ample food for thought for both academic and general readers.