WHAT if, on October 14, 1066, William the Conqueror had lost the Battle of Hastings? Would England have remained a backwater outside the mainstream of European civilizations?

What if the Enigma code had never been cracked? Would this even matter if Lord Halifax had become Prime Minister instead of Churchill? And how would the war have ended if America had decided not to drop the two atomic bombs on Japan?

In More What If, the sequel to the acclaimed What If?, more of the world's leading historians, including Geoffrey Parker, Theodore K Rabb, Cecilia Holland and Caleb Carr, postulate on what might so easily have been.

An added dimension to More What If? is the inclusion of several incidents away from the battlefields, though intrinsically linked to them. What if Lenin was too late to start the Russian Revolution? What if the Chinese had found America 500 years before Columbus? Or, perhaps most interestingly, what if Pilate had set Jesus Christ free?

With wit, verve and unparalleled insight, More What If? is a tantalizing glimpse of what might have been. (Macmillan £18.99).