Choose one type of weapon. You can also choose unarmed strike or grapple (or ray, if you are a spellcaster) as your weapon for purposes of this feat.
Proficiency with selected weapon, base attack bonus +1.
You gain a +1 bonus on all attack rolls you make using the selected weapon.
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.
A fighter may select Weapon Focus as one of his fighter bonus feats. He must have Weapon Focus with a weapon to gain the Weapon Specialization feat for that weapon.