'Inventive in its conception and faultless in its methodology, this is a subtle research by two cautious, succinct and profound thinkers on a challenging theme calling for a prismatic perceptive power and bearing fascinating reflections. I can’t recommend this book strongly enough to historians, ethnologists, philosophers of religion, linguists, students of medieval Arab culture, or adherents of the view that human culture and civilisation is a collective product – Hellenic, European, Arab, Jewish.'Stavros Nikolaidis, in Journal of Oriental and African Studies, Volume 22, 2013