Spell Mastery
From Compendium of Worldly Lore
Needs review
Source: Player's Handbook
Description: You are so intimately familiar with certain spells that you don't need a spellbook to prepare them anymore.
Prerequisites: Prepared Arcane Caster Level 1
Each time you take this feat, choose a number of spells equal to your Intelligence modifier that you already know. From that point on, you can prepare these spells without referring to a spellbook.
Normal
Without this feat, you must use a spellbook to prepare all your spells, except read magic.