Spell Focus( Player's Handbook v.3.5, p. 100)
Choose a school of magic, such as illusion. Your spells of that school are more potent than normal.
Augment Summoning (PH) , Beckon the Frozen (Fr) , Black Lore of Moil (CAr) , Enchanting Song (RS) , Energy Gestalt (CM) , Greater Spell Focus (DD) , Greater Spell Focus (FRCS) , Greater Spell Focus (TB) , Imbued Summoning (PH2) , Mastery of the Dead (PE) , Misleading Song (RS) , Energy Abjuration (CM) , Greater Spell Focus (PH) , Ability Enchancer (DC) , Embody Energy (EE) , Evasive Maneuvers (EE) , Proteus (EE) , Dragonmarked Summoner (Dra) , Evokers Mark (Dra) ,
Add +1 to the Difficulty Class for all saving throws against spells from the school of magic you select.
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new school of magic.