Professo r Creswell explains how Muslim architecture was bo r n', as well as describing, he cultural influences which helped to mould it a nd which were responsible fo r its early duality. As the seat of the Umayyad dynasty was in Syria, Umayyad architecture was dominated by the Hellenistic traditions of the Christian architecture of the country befo r e the Arab conquest. But when the Umayyad dynasty fell a nd the seat of the Khalifate was transferred to Baghdad the effect was similar to the effect of the transfer of the capital of the Roman empire fr om Rome to Constantinople, everything became mo r e eastern, i.e. Perisan, a nd the influence of the Hellenistic art of Syria weakened. Thus was bo r n the Imperial art of the ',Abbasid Empire which extended as far no r th as Samarqa nd, as far south as Bahrain, a nd as far west as Egypt, whilst the half-Hellenistic Umayyad architecture lived on in Spain, whither it had been taken by ',Abd ar-Rahman, the last survivo r of the Umayyad family, a nd the thousa nds of Syrian refugees who followed him. This book, which is ba sed on his larger wo r k in two folio volumes published by the Clarendon Press, Oxfo r d, in 1932 a nd 1940, contains 72 plates a nd over 60 drawings.