This book deals with the isolation regime of Abdullah Öcalan, who was arrested in 1999 and since then has been imprisoned as a sole inmate in the High Security Prison of Imrali in Turkey. The aim is to investigate the detention conditions imposed on the detainee and to find out about the allegations of human rights violations in this case of isolation. The principle of the prohibition of torture, laid down in Art.3 ECHR, serves as the basis for this research and will be analyzed, thereby clarifying the scope of protection. On the momentous occasion of the sudden end of the isolation regime in November 2009, this work aims at imparting a comprehensive knowledge about the development of the isolation regime, the perception of the CPT regarding human rights conformity as well as the controversial judgments of the European Court of Human Rights and consequently the improvements that have been achieved by transferring five convicts to Imrali. The relevance of the CPT standards as well as the role of the Committee as a preventive organ in setting human rights standards and its influence on member states (dialogue with Turkey) will be analysed.