Technology revolutionized warfare when the first man learned to fashion a club, and the revolution shows no sign of slowing down. The PBS documentary “Ground War” (out on DVD) traces developments in weaponry from the ancient Greeks, who went to battle in bronze helmets and with iron swords, into a near future of robot weapons. As the experts interviewed for this fast-paced four hours point out, changing technology has always involved greater range, destruction, accuracy and rate of fire, and one advance spurs an inevitable pushback. The Romans finally defeated the Greeks after they developed steel swords.
