This article aims to present the notion of justice, based on the book The Theory of Justice (1971) by John Rawls . The intention is to delimit the aspects that refer to political philosophy and philosophy of right, in order to show that Rawls' theory goes beyond the legal-political approach, also encompassing the social, insofar as, although the principles display a top-down approach, the theory aims at social cooperation, whose presupposition is the idea of human solidarity, that is, the common good for all. In this sense, my article will focus on the concept of justice and its philosophical, legal and social aspects. In the first part of the Theory of Justice, Rawls defines the basic ideas that will develop throughout the book. In the sec...