Three children are arguing about who should own a flute. The first child has had music lessons and is the only one who can play the flute. The second child is poor and has no other toys. The third child has made the flute with great perseverance. With this parable, Amartya Sen, one of the most important thinkers of our time, opens his book on the idea of justice. It is dedicated to John Rawls, yet it distinguishes itself from the most influential theory of justice of the 20th century. Those expecting another abstract discussion of the institutional foundations of a just society will be disappointed. However, those who wonder what these theories actually contribute to combating real existing injustices will gain greatly from it. Sen indeed questions the plausibility of such efforts in pure terms.