Modern state law excludes populations, peoples, and social groups by making them invisible, irrelevant, or dangerous. In this book, Boaventura de Sousa Santos offers a radical critique of the law and develops an innovative paradigm of socio-legal studies which is based on the historical experience of the Global South. He traces the history of modern law as an abyssal law, or a kind of law that is theoretically invisible yet implements profound exclusions in practice. This abyssal line has been the key procedure used by modern modes of domination - capitalism, colonialism, and patriarchy - to divide people into two groups, the metropolitan and the colonial, or the fully human and the sub-human. Crucially, de Sousa Santos rejects the decadent pessimism that claims that we are living through 'the end of history'. Instead, this book offers practical, hopeful alternatives to social exclusion and modern legal domination, aiming to make post-abyssal legal utopias a reality.