Needs review
Source: Epic Level Handbook

Description: Choose a school of magic, such as illusion. Your spells of that school are far more potent than normal.

Prerequisites: Epic Level, Greater Spell Focus, Ability to cast at least one 9th-level spell of the selected school

Add +6 to the Difficulty Class for all saving throws against spells from the school of magic you select to focus on. This overlaps (does not stack with) the bonuses from Spell Focus and Greater Spell Focus.

Special

You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a different school of magic.