Respect for and promotion of human rights have come to be seen as the basis of legitimacy of modern Western civilization. There is nevertheless a striking contrast between our common view on the importance of rights and our profound disagreement on their meaning and content. This disagreement has become increasingly sharp in the last decades, due to the emergence of controversial "new rights". The author gives an in-depth account of the most important moral debates, exploring the ethical and political foundations underlying the different understandings of rights. In the first part, he focuses on the role played by the ideas of "good" and "reason" in the Thomistic-Aristotelian and Kantian traditions; and he compares those concepts with the main currents of contemporary liberalism, which, among other things, focus on our emancipation from the limits of nature. The book attempts to show the dehumanizing effects of denying the relevance of integral human good in defining the scope of human rights and liberties, and offers an alternative way forward for our understanding of human rights in a pluralistic society.