This book is the first full-length work concerning the restoration and excavations carried out at Qal'at Sem'an in Syria in the twentieth century. It was written by the notable architect and archaeologist Georges Tchalenko based on his notes, plans, photographs and sketches as he undertook the work in the years before and during the Second World War. Left unpublished at the time of his death during the Lebanese Civil War, it is published here for the first time in the original French with an English translation. The text is richly illustrated throughout and accompanied by a biographical essay by John Tchalenko and an introduction to the historiography of Qal'at Sem'an and Symeon Stylites by Emma Loosley Leeming.