Lost Odessey Question!!

In the game lost odessye wich i like a lot my characters are at level 28 and but some speell they cant use becuase it is still empty in the spell book. Where can i get these spells do i buy them or what. Some of them come naturally with leveling up others do not help please

Your characters gain access to higher levels of magic as they level up. If, for instance, Jansen has lvl 4 Black Magic, then levels 5, 6, 7 and 8 will remain blank in the spellbook until he has gained those levels.

Additionally, some spells have to be bought from shops, learned from NPCs or found in chests.

Mmyup.