Here is a book that readers who are interested in multi-agent systems will find useful. The author, Andrew Ilachinski is also a reader of this blog, by the way -- it's called "Artificial War: Multiagent-Based Simulation of Combat" and provides an examination of the thesis that what happens on a battlefield (though the arena can be much more general of course) is a self-organized emergent phenomenon that can be understood, at least in part, by examining relatively "simple" underlying rules. In essence, mobile cellular automata. The book summarizes work that dates back to 1997 and was sponsored at different times by the US Marine Corps and Office of Naval Research. Among many applications of this research -- consider the applications for computer games and simulations, as well as for visual effects (think, even more realistic epic battle scenes and crowds).
Anyway, here's the link
TOC and index can be downloaded here