In 1990 the then Minister for Culture, Hedy d’Ancona, issued the Delta Plan for Cultural Preservation: a large-scale and national program to thoroughly improve collection storage conditions in Dutch museums. This signalled the start of a transformation of the Dutch museum.he reason for this radical transformation of Dutch museums was the pending privatization of the country’s national museums. From the beginning of the 1990s, national museums had to stand on their own feet. That gave the museum visitor a new position: the museums were forced to engage the public and did so with conviction. This new approach bore fruit: the public has been flocking to museums in increasing numbers and by doing so, have further transformed the Dutch museum. Museums want to open up their collections to everyone while protecting these collections as well as possible. To align these ambitions Dutch museums have engaged in an unprecedented construction boom. The desire to be able to study the results of those building activities brought the TUDelft to approach the Cultural Heritage Agency of the Netherlands (RCE) to undertake a joint investigation into the transformation of museums in the Netherlands since 1990 together. This study shows that much has been achieved to realize the two ambitions of better collection management and increased visitor numbers. The RCE continues to endeavour to further align those two conflicting ambitions, which is why we develop and disseminate knowledge about the safety of heritage including researching climate control possibilities for collection storage and display. In her policy letter Heritage Counts (2018–2021), Minister Van Engelshoven (Education, Culture and Science) opted to further both ambitions: conservation of, and employing the unifying power of heritage. Museums particularly embody the contradiction between preservation and accessibility. They exist to preserve valuable and often vulnerable objects of art, history, science and daily life. But they are also there to make us take ownership of those objects. The challenge for museums is to find the best relationship between their need to ensure the safety of their top pieces and prevent any risk of damage. At the same time, they want to be hospitable and open to everyone who wishes to enjoy their collection. An object has to be preserved for many generations and the current generation must be able to become acquainted with and enjoy it in large numbers. In other words: the museum must be comfortable for both visitors and collection, now and in the future. The RCE and the TU Delft Section for Heritage & Architecture often collaborate. This time we found common ground in research into the transformation of museums. Architects and museum managers are constantly faced with the task of realizing this transformation as fittingly as possible. Their mutual communication and coordination is crucial. This study hopes to contribute to that. The cooperation of the museums investigated has been of great importance in this regard. By making data available and sharing insights and experiences, they have made it possible to investigate the transformation on museums in the Netherlands. The result presents a fascinating picture of the metamorphosis of Dutch museums.