Several of the contributions to this issue on authenticity conclude by asking whether the concept of authenticity is a credible criterion. According to UNESO’s Operational Guidelines for the implementation of the World Heritage Convention, a monument designated as world heritage possesses ‘Outstanding Universal Values’ (ouv). It also meets the conditions of integrity and authenticity, at any rate when it comes to cultural heritage. In accordance with The Nara Document on Authenticity (1994), and taking account of global cultural diversity, authenticity can be based on a wide variety of attributes.Two Dutch World Heritage monuments, the Rietveld Schröder House (1924) and the Van Nelle Factory (1925-1931), belong to the architecture of the Modern Movement. In the nomination dossiers for these two heritage buildings authenticity was substantiated in different ways. But in both cases, as has become customary for Modern Movement monuments, ‘design authenticity’ was deemed of great importance. Has the concept of authenticity been expanded to such an extent that it has ended up being applied arbitrarily? In this author’s view, authenticity can most certainly be a criterion of quality, provided a clear and credible definition is employed within the specific cultural context.