Just before World War I, Pierre J.H. Cuypers completed Castle de Haar, after more than two decades of building activity. Assisted by his son Joseph, during this period the architect had restored, reconstructed and completed a ruin with a history of more than seven centuries, resulting in a veritable Gesamtkunstwerk: an enclosed castle with an outer bailey, a stable complex, a chapel, a village, gardens and a park. The complex was designed entirely in the medieval style, but built with the most modern materials and equipped with then-advanced installations such as elevators, central heating and electric lighting. At the beginning of the twentieth century, the international jet set resided here, just a stone's throw from Utrecht, and the castle still serves as the vacation home of the noble Van Zuylen van Nijevelt van de Haar family during the month of September. Now that the restoration of the largest and most fairytale-like castle in the Netherlands has been completed, a comprehensive monograph is being published. The much new knowledge gained during the work on this "canny monument" has been incorporated into this book, which, in addition to the aspects mentioned, also covers the long history of the estate and the castle, the residents, the collection and the restoration itself.