Niall Ferguson's book takes aim at several myths about WW I and integrates several ideas in one volume. Several have been addressed before in other forums to better effect, and he has missed, I think some salient points. These include the British desire (under Churchill, no less) to maintain total naval supremacy in the face of the German Navy's dreadnoght buildup. British intelligence also failed to anticipate German chemical research success in fixing nitrates from the atmosphere to produce explosives. This allowed German industry to continue to operate at full capacity despite the blockade.
Ferguson's industrial and economic capabilies are very consistent with those found in Paul Kennedy's 'Rise and Fall of the Great Powers' (1987), but Kennedy says it better.
The perception of war by the public before and during WW I is quite enlightening, as is his conclusion that some men actually enjoyed the killing. There is much anecdotal evidence to support this. For many men war is the only time that they achieve any importance or success, and they fade into obscurity afterwards. Although a different war and front, picture Sgt Steiner from 'Cross of Iron' and you've got the picture.
In sum, Pity of War is an extremely well researched tome that attempts to dispel some of our most cherished myths. I can only give it 4 stars due to its occassional lack of focus. It is required reading for any politician considering sending soldiers, sailors, or airmen into battle.