Since the first interactions between Christians and Muslims, a central point of contention has been the nature of God in relation to the doctrine of the trinity and divine oneness. Yet the belief that God is one is vociferously upheld by Christians, Jews and Muslims alike.

In this detailed historical study and subsequent analysis, Dr Michael F. Kuhn explores the teaching of two Arab Christian theologians from the Abbasid Era (750-1250), 'Abd Allāh Ibn al-Ṭayyib and Iliyy