Following on from and completing the volume Monuments and Sites XII "The World Heritage List, Filling the Gaps: an Action Plan for the Future", published in 2005, this new volume takes a comprehensive look back at the work done among other by ICOMOS since 1976 as an advisory body to the World Heritage Committee in relation to the criteria for the outstanding universal value (OUV) required by the Convention as a precondition for the inscription on the World Heritage List. It contains chapters on: the development of the OUV concept; characteristics of the OUV criteria i.) - vii.) and their justification; different aspects of using the criteria; other requirements for inscription; reasons for non-inscription; as well as conclusions and recommendations and a series of annexes, some of which represent previously unpublished material.