I read a book called "The Last Full Measure: How Soldiers Die in Battle" and in that book, which traces warfare from ancient times (through the Iliad) to modern day. In the WWII section, there was one frightening statistic: 50% of all casualties were caused by indirect fire.
Pirate try also:
http://www.amazon.com/Sharp-End-The-Fighting-World/dp/068416728X