Almost every country today contains adherents of different religions and different secular conceptions of the good life. Is there any alternative to a power struggle among them, leading most probably to either civil war or repression? In this important new work of political philosophy, Brian Barry argues that justice as impartiality offers a solution. The follow-up to his prize-winning book Theories of Justice, it offers a contemporary restatement of the Enlightenment idea that certain basic principles can validly claim the allegiance of every reasonable human being.