War Before Civilization: The Myth of the Peaceful Savage by Lawrence H. Keeley
Discusses warfare with both anthropological and ethnological evidence.
Opens with the discussion of the Hobbesian and Rousseauan views on human nature and war, and the views of various scholars and how this colors their evidence.
A scholar calls the palisades and ditches of Neolithic civilization, but many have heavy arrow deposits, especially near the gates, and some were burnt at the same time. One burnt palisade fell on a man who had been shot in the back at the same time, falling on the baby he was carrying and crushing the baby.
Covers such issues as frequency (peaceful societies are not, in fact, completely unknown), death toll, mobilization rates (comparable to civilized even before you factor in that all mobilized men in bands or tribes fought), whether civilized armies can fight primitive ones (generally only by adopting many of their tactics including, often enough, hiring them), what causes the wars, how peace can be made, comparative atrocities, and more.
Can be grim reading. Especially the atrocities.