The Ninjas today are the stuff of myth and legend in comics, film and electronic games. But once they were real, the medieval equivalent of the SAS: spies, saboteurs, and assassins. In Ninja John Man takes us from their origins over 1,000 years ago, from their heyday in the civil wars to the ‘last of the ninjas’, Hiroo Onoda, who held out in the Philippine jungle for 30 years.