Armor Use - Allows you to equip progressively more powerful forms of armor and to get more out of the armor you already wear.
Athletics - Gives you access to Special Abilities that change your physical capabilities, such as increasing land speed.
Dodge - Improves your defenses against ranged attacks. The defference between your Dodge and your opponent's Rifle or Pistol Skill affects how much damage you take. Dodge also determines your Melee Defense.
First Aid - Gives you some Abilities that heal. This Skill is required to use items created with the Medicine and Mutagenics Skills.
Group Tactics - Allows you to activate buffs on teammates during combat.
Melee - Allows you to inflict more damage and use more effective weapons in melee combat. The difference between your Melee and an opponent's Melee Defense affects how much damage you do.
Pistol - Allows you to inflict more damage and use more effective types of pistols. The difference between your Pistol and an opponent's Dodge affects how much damage you do and your chances of scoring a critical hit.
Rifle - Similar to Pistol and Melee in its affects on damage and weapon use. Like Pistol, the paired Ability is Dodge, and the difference between these two Skills helps calculate damage.
Social - Enables you to finagle better deals from Merchants and allows you to conceal your faction allegiance.