Ability Score
Dexterity (Dex) encompasses several physical attributes including hand-eye coordination, agility, reation speed, reflexes, and balance. Dexterity affects a character's reaction to a threat or surprise, his accuracy with thrown weapons and bows, and his ability to dodge an enemy's blows. It is the prime requisite of rogues and affects their professional skills. A rogue with a Dexterity score of 16 or higher gains a 10 percent bonus to the experience points he earns.

Reaction Adjustment modifies the die roll to see if a character is surprised when he unexpectedly encounters NPCs. The more positive the modifier, the less likely the character is to be surprised.

Missile Attack Adjustment is used to modify a character's die roll whenever he uses a missile weapon (a bow or a thrown weapon). A positive number makes it easier for the character to hit with a missile, while a negative number makes it harder.

Defensive Adjustment applies to a character's saving throws (see Glossary in Player's Handbook) against attacks that can be dodged--lightning bolts, bouldersm etc. It also modifies the character's Armor Class (see Glossary in Player's Handbook), representing his ability to dodge normal missiles and parry weapon thrust. For example, Rath is wearing chain mail, giving him an Armor Class of 5. If his Dexterity score is 16, his Armor Class is modified by -2 to 3, making him harder to hit. If his Dexterity score is 5, is Armor Class is modified by +2 to 7, making him easier to hit. (In some situations, beneficial Dexterity modifiers to Armor Class do not apply. Usually this occurs when a character is attacked from behin or when his movement is restricted--attacked while prone, tied up, on a ledge, climbing a rope, etc.)