Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - General Skill Books?

When you level up you can assign points to the different skills (Man at arms, Hydro, Geo, Scoundrel, etc.) in your Character sheet. Each time you assign a point in one of those, you can learn more spells/skills of this school.

1 point = 3 spells/skills
2 points = 5
etc.

Under your character portrait on the left, you will see an icon under each face. One for Inventory, the other for Skills. If you click on Skills you will see a tab for each schools and the number of spells/skills you have learn and that you can still learn. For example you may have learn 2 out of 3 skills in the Man at Arms school.

Also, if you learn a spell/skill, it is possible that it will cost more Action points in combat if you have only 1 point in your character SKills for this school.
Example: Fireball spell cost 9 Action points to cast if you have 1 point in Pyro school skill
It will cost 7 I think if you have 2.
And perhaps less if you have 3 or more.

You cannot learn some spells/skills unless you have the good level.
Example: (I think) To be able to read and learn the Summon Ice Elemental Book spell, you need to be level 7.

It is an interesting way of learning spells/skills and becoming better. Each point make a huge difference in your fights and it is very fun to make that choice everytime you level up.