Did you know that there are at least two places in Nigeria where the local appellate courts have ruled that a five-year interval is possible between conception and birth? This supposed offence against reason, however, is in fact an example of what Kadri calls "manipulated mercy", because what the decree indicates is a desire to avoid stoning women who have become pregnant as a result of adultery or other illicit sexual activity.
The words "shariah law" make many people in the west anxious. You may recall that when Rowan Williams said in 2008 that it was "unavoidable" that British law would come to accommodate certain aspects of it, there was a bit of dismay among those who had not looked at the fine print of his remarks. (He was basically talking about local arbitration; not so stirring.) "Panics are always irrational," notes Kadri, and indeed there is a wide split within Islam itself, between and I put this in the broadest possible terms those Muslims who believe in looking at things rationally and those who believe that our only business is to do God's will, and don't ask questions. (The question hinges on a theological dispute: was the Qur'an created by God, or had it always existed? The number of people who have died as a result of this quibble is beyond computation.)
This is an extremely valuable book. Its first half deals with the history of Islam, and any misgivings you might have had about its contemporary relevance will be dispelled very quickly. Arguments about the life of the prophet and the ructions that followed immediately after his death are still going. The religion he founded was always mutable, open to revision, even while the Qur'an was being composed, or dictated.
One impression that emerges strongly is the extremely violent temper of the times. Passions seemed to have run high in those days; there are accounts here of either rulers or troublemakers who have had molten silver poured into their ears and eyes, or had their tongue fed to cats, or been forced to watch their chopped-off limbs being roasted in an oven. Caliph al-Ma'mum in 833 inaugurated an annual springtime offensive against Byzantium; one has to feel for the inhabitants of that city whenever April rolled round and they saw the caliph's army on the horizon again.
Knowing this stuff is important, and Kadri takes us through it wonderfully well. He has a great grasp of the facts and this is my favourite thing a good, dry sense of humour. The second half of the book, in which he travels to various parts of the Islamic world and talks to madrasa students, theologians and human rights campaigners, has been compared unfavourably to the first half by some reviewers, but I think this is only because the first half is so readable and fascinating.
I like Kadri's observation on the cleric who, while denouncing the frivolous habit of watching television, says it is fine to appear on it, being pious. Kadri notes that the cleric has found his own reasoning quite persuasive on the point, and is regularly on the box himself.
It's a minefield, shariah law, then, and when you're in a minefield, you need a guide. This is as good as we have right now, and don't let the laudatory quote from Boris Johnson on the front cover put you off. And for all the stories of cruelty, or religiously inspired sadism (do the surgeons at King Fahd hospital in Medina, Saudi Arabia sleep soundly after performing a forcible blinding, I wonder?), don't forget that we were still ducking our accused in barrels of water or asking them to hold red-hot pokers to determine their guilt or innocence, when Islamic courts were listening to reasoned evidence, and proposing settlements which look enlightened even today.
To order Heaven on Earth: a Journey Through Shari'ah Law for £7.99 with free UK p&p call Guardian book service on 033 333 6846 or go to guardian.co.uk/bookshop
