This is an excellent "food for thought" book about different conceptions of justice. Sandel takes complex philosophical concepts and makes them simple to understand. This book opened my mind a little bit more to the reasoning behind the position of people I disagree with on various social issues and yeah, it even made me rethink a few of mine. Disturbing. 
 He discusses three main concepts of justice: Justice as the greatest happiness for the greatest number, Justice as the respect of the freedom of choice, and justice as cultivating virtue and the common good. Sandel believes in the third approach. 
 I have to admit I am more on the "freedom of choice" gang: we agree on some fundamental rights (life, education etc) and for the rest, we respect personal choice.