This book is focused on the issue of peremptory norms (jus cogens), formulated in the 1969 Vienna Convention on the Law of Treaties, and its applicability in core Human Rights implementation. It thus examines the nature of jus cogens and its formation vis-à-vis Human Rights andadvocates for the additional value that jus cogens can bring to core Human Rights implementation. The focal problem that the book addresses is the lack of clarity attached to jus cogens and its subsequent effects oneffective core Human Rights implementation. To wonder why jus cogens remains ineffective and to see what can be done, and by whom, to enhance its impact on core Human Rights is the main goal of this book. The authors firmly believe that the jus cogens concept brings a significant contribution to core Human Rights implementation, putting them at the foundation of the international legal order. This effect is substantial tothe future core Human Rights development, but, depends also on the future redefinition of jus cogens itself.