This study investigates the so-called thematic approach as a method available to the United Nations Commission on Human Rights to take cognizance of and to react upon violations of human rights worldwide. To this end, three different thematic procedures, the Working Group on Enforced or Involuntary Disappearances, the Special Rapporteur on Torture and the Working Group on Arbitrary Detention, have been subjected to detailed scrutiny. The analysis of the three selected thematic procedures reviews in detail their establishment, the development of working methods and techniques such as routine transmissions, urgent appeals, on-site visits and annual reports and concludes that since 1980 thematic procedures have managed to establish, consolidate and institutionalise their working methods within the United Nations system of human rights protection. At the same time, it also concludes that the effectiveness - the ability to produce a desired effect - of the thematic approach must be deemed extremely limited. In the light of these two conclusions, the study undertakes to initiate a discussion concerning the supposed changing nature of the international legal order: a move away from the so-called statist presumption of international law towards a vision of international law governing a constitutional order presenting more and more hierarchical features. The author concludes that, notwithstanding the desirability of achieving this objective, it is premature to assume such a change of paradigm.