This essay aims to introduce and analyze the prohibition of torture, inhuman or degrading treatment or punishment. It provides a general overview on the historical and institutional background of this absolute right as well as presents the major conventional achievements of the last four decades. The main emphasis of this work lays on the Council of Europe, on its European Convention on Human Rights and Fundamental Freedoms and on its unique and pioneer judiciary body, the European Court of Human Rights. It also gives an introduction to the essential features of torture and other forms of ill-treatment, such as its position and weight amongst other fundamental human rights, its core characteristics and its forms of realization. The main part of the thesis is deals with the comprehensive jurisprudence of the European Court of Human Rights through the prohibition of torture. It demonstrates the major principles and concepts the Court has developed over the decades, such as the hierarchy between the terms ‘torture’, ‘inhuman’ and ‘degrading’, its progressive interpretation of the prohibition and the expanding scope of its jurisdiction.