Skill Scrolls are used to learn new skills. These range from the combat abilities of the characters, to the production 'recipes' used to produce a given item.
Skill Scrolls must be purchased from skill merchants, or in some cases other merchants. Skills are often limited by level, and sometimes by promotion. For example the Spell Mage Blast may only be learned by a mage who has attained level 20, and completed the first promotion challenge to become a WizMage.