The Chehel Sotun or of the Forty Columns Pavilion is one of the most important monuments that arose in Isfahan after Shah Abbas, in 1598, made it the capital of the Safawid Empire. The great palace was used to receive foreign delegations who came to visit from all over the world and, later, for the same coronation of the Shah. A large hall full of murals, miniatures and wall decorations is the most important architectural element, and is preceded by the "Throne Room", and a large porch supported by tall wooden columns. Canals, pools and fountains surround the pavilion, located in the centre of a large garden inscribed as "Persian Garden" in the list of UNESCO World Heritage, that enrich the charm with the fresh murmur of water and that have been brought to light or restored. On the basis of the relation of the monument with the urban layout of the Safawid Isfahan and thanks to the evidence brought to light during the restoration works, this volume deals with the attribution of the parts of the palace that have arisen over time, to the rulers involved in its construction. It also exposes the careful considerations and the historical and formal evidence that determined the design choices for the reconstruction of architectural elements and for the execution of the restoration pictorial. The architectural survey, carried out during the restoration, presents the first drawings of the pavilion and allows better understanding the grandiose architectural structure and the design intentions of the sovereigns who have determined the current appearance.