Yeah man...
Use my schooling for example. My school is supposed to teach you almost everything about cars... and i do mean everything (some science is also involved). As any other school, there are assignments and lab work to teach us about the certain area of study (i already passed transmissions, engines, and i'm currently in driveability).
There are grades given out, and even though some people may score very high on assignments and tests, not everything we cover do we actually work on. Or, some people may be good at bookwork, but can't do shit hands-on... know what i mean?
In my opinion, reading books on how to play airsoft, or any other similar game is unnecessary. I myself am a better learner when i'm actually doing it, or experiencing it. Not sayin that i'm a dumbass when it does come to bookwork, but i hope you know what i'm sayin.'
You can keep looking around, hope you find what you're looking for. Did you try googling it
? Never know, might have some online resource to get some info. But yeah dude, i learned how to play myself... not a book. And if i really needed that kind of training, then you'll prolli see me with a real gun and a drill instructor at boot camp.