It would be hard to overstate the philosophical significance of John Rawls's TJ. It articulates and defends an egalitarian conception of liberalism and distributive justice that consists of two principles of justice: a principle of equal basic liberties and a principle that distributes social and economic goods and opportunities so as to be to the greatest benefit of the least advantaged. Rawls defends this liberal egalitarian conception of justice primarily as an alternative to utilitarianism. He situates his defense of this liberal egalitarian conception of justice within the social contract tradition by arguing that his principles of distributive justice would be preferred to utilitarianism and other rivals by parties to a social contract in which they were represented fairly, that is, as free and equal moral persons. This explains why Rawls calls his conception justice as fairness and the importance of the hypothetical original position as a way of modeling a fair initial position from which principles of justice might be selected. Rawls thinks not only that justice as fairness would be preferred to utilitarianism in a fair social contract but also that it provides a better reconstruction than utilitarianism of our considered views about individual rights and justice. Though Rawls's primary focus is on the justice of the basic structure of society, his critique of utilitarianism, his contractualist methodology, and his defense of equal basic rights have had much wider philosophical influence, extending to a variety of issues in ethical theory and normative ethics. In this way, the publication of TJ transformed and reinvigorated ethics as well as political philosophy.

Any assessment of justice as fairness must address the adequacy of Rawls's contractual argument for his two principles of justice and against utilitarian rivals. In this context it is worth noting that Rawls has two kinds of ambition. On the one hand, he has the substantial but comparatively modest ambition to defend a more egalitarian alternative to utilitarianism. He would succeed in this ambition insofar as parties in the original position would indeed prefer his two principles of justice to traditional utilitarian rivals. On the other hand, Rawls also has the more ambitious aim of showing his two principles of justice to be uniquely plausible, that is, to be superior to all reasonable alternatives.