Yazarın ele aldığı konu, Osmanlı İmparatorluğunda Arab – hıristiyan azınlıkların menşeini ve aynı zamanda Mezopotamya, Suriye, Filistin bölgesinin islami devirde geçirdiği değişikliği anlamak bakımından önemlidir. Yazar J. S. Trimingham Sudan, Mısır, Suriye ve Lübnan'da uzun yıllar kalıp dinler tarihi, sufizm ve hiristiyanlık üzerinde araştırmalar yapan bir uzmandır. Kitapda, islam fetihlerinden sonra "arabize" edilen sami hıristiyan kavimlerden çok, eski devirlerden beri arapça konuşan arap toplulukları arasında hırıstiyanlığın yayılışı ve pratikte nasıl uygulandığı üzerinde duruluyor.

Piety and Philanthropy cannot very well be divorced in medieval Islam, but by observing the Moslem hospitals and other institutions of charity and social welfare it is seen quite clearly that the idea of public assistance had developed beyond what piety alone could have produced. A discriminating and comprehensive consideration of the necessity of public assistance and social welfare, beyond mere religiosity, may be said to have been responsible for the qııality and quantity of the hospitals of Islam. Moreover, the humanitarian features of the Islamic medieval hospital must not be allowed to eclipse its high medical standing per se. The hospital was one of the most developed institutions of medieval Islam and one of the highwater marks of the Moslem civilization. The hospitals of medieval Islam were hospitals in the modern sense of the word. In them the best available medical knowledge was put to practice. They were specialized institutions. Unlike the Byzantine hospitals, they did not have a mixed function of which the treatment of the sick was only one part.