Going on the assumption that all skill books contain related info towards the given skill, as I shamelessly admit to not have read half of them, one in particular... I don't understand.

http://www.uesp.net/wiki/Skyrim:The_Warrior%27s_Charge and it's relation to Conjuration, what is that exactly?

Funny you mention that, I haven't read them and haven't really paid attention as well.