Throughout history, great and terrible events have often hinged upon luck. Andrew Roberts has asked a team of twelve leading historians and biographers what might have happened if major world events had gone differently?Each concentrating in the area in which they are a leading authority, historians as distinguished as Antonia Fraser (Gunpowder Plot), Norman Stone (Sarajevo 1914) and Anne Somerset (the Spanish Armada) consider: What if?

Robert Cowley demonstrates...