The subject matter of the volume is the former Church of Saint Sophia, today"s Ayasofya Museum built by Justinian the Great in 532-37. After it was built, for many centuries both Christians and Moslems believed that it was not the talent, experience and courage of its builders but the hand of God that must have made such a monument possible. Scholars regard the building as a unique synthesis of the architectural traditions which existed in the sixth-century Byzantine world. None of the master architects of the Byzantine Empire nor those of the West would dare to repeat its plan during the following centuries. St Sophia witnessed the golden days of Constantinople, its suffering at the hands of the soldiers of the Fourth Crusade, its Palaiologos revival and its fall to the Ottoman Turks. In a single day the ringing of its bells were replaced by the call of "müezzins". After Constantinople was turned into the capital of the Ottoman Empire the monument became a source of legends and stories for Moslem writers. Its plan and size served as a source of inspiration and challenge for the Ottoman architects.The book covers the early history of Byzantium and Constantinople, the first and second churches of Saint Sophia which were built on the same spot, the Nika (Victory) Riots and construction of present-day building and its history first as a mosque and later as a museum. The last part of the volume deals with its surviving mosaics and includes pictures of all of them. The text is supplemented with plans and drawings of the Fossatis who restored the monument in the nineteenth century.