Just because you put a holy book in people’s hands does not mean they will understand it — Americans buy more than 20 million new ones every year to add to the four that sit in the average US house. Yet one Gallup survey found that fewer than half of Americans can name the first book of the Bible (Genesis), and only a third know who delivered the Sermon on the Mount (the evangelist Billy Graham is a popular answer). The situation is worse with Islam. The archaic language and high-flown verse of the Koran, while inspiring to some, can also be difficult to understand for even highly educated Arabic speakers. Only 20 per cent of Muslims speak Arabic as their first language.