When I read the magic book, it was explaining the basics of basics.
Besides, in the book it also explains how to adjust power, and other ways to tweak the spells.
Of course, in order to learn these things, time is necessary.
This is not a game, and time is limited. But, I should also avoid learning too much from the crystal balls since their efficiency would be bad.
Judging from the other heroes' actions, I am currently the only one that can read this world’s letters.
It may be important to make use of this advantage.