Called "How to Make War" and it describes the mechanics, the theory, and the variables that impact the prosecution of warfare. The Wargames book was, in my opinion of course, a derivative which attempted to re-contextualize the information from HtMW into something more directly 'wargame like' but, again in my opinion, it left out too much to be useful even for that.
The Complete Wargames Handbook
http://www.hyw.com/Books/WargamesHandbook/Contents.htm
Is about how to make computer war games.