[1]In the book, Sen makes a radical break with the traditional notion of homo economicus, or 'rational economic man' as motivated mainly by self-interest.

In his introduction to The Idea of Justice, Sen states that "the strong perception of manifest injustice applies to adult human beings as well (as children).

What moves us, reasonably enough, is not the realization that the world falls short of being completely just – which few of us expect – but that there are clearly remediable injustices around us which we want to eliminate."

One of Sen's main arguments is that the project of social justice should not be evaluated in binary terms, as either achieved or not.

He credits Rawls for revitalizing the interest in the ideas of what justice means and the stress put on fairness, objectivity, equality of opportunity, removal of poverty, and freedom.

However, Sen, as part of his general critique of the contractarian tradition, states that ideas about a perfectly just world do not help redress actual existing inequality.

The Idea of Justice has been described by The Economist as a "commanding summation of Mr Sen’s own work on economic reasoning and on the elements and measurement of human well-being".