Strength measures a character's muscle, endurance and stamina. Strength is especially important to fighters, barbarians, paladins, rangers and monks because it helps them prevail in combat.

Dexterity measures a character's hand-eye coordination, agility, reflexes and balance. Dexterity is most important to rogues, but also helps characters that typically wear light or medium armor (barbarians and rangers) or none at all (monks, wizards and sorcerers) and any character that wants to be skilled in ranged combat.

Constitution measures a character's fitness, health and physical resistance to hardship injury and disease. Constitution is important to all characters because it affects hit points. Wizards and sorcerers gain further benefits from a high Constitution as it helps to prevent their spells from being disrupted if they are hit in battle.

Intelligence measures a character's memory, reasoning and learning ability. Intelligence is most important to wizards and characters that want to start with a wide variety of skills.

Wisdom measures a character's enlightenment, judgment and common sense. Wisdom is most important to clerics, druids, paladins and rangers, but helps any character that wants keen senses and the ability to resist controlling magic. It also affects the armor class of an unarmored monk, making the monk easier or harder to hit in combat.

Charisma measures a character's force of personality, persuasiveness, personal magnetism and ability to lead. Charisma is most important to paladins, sorcerers and bards, though it also helps clerics turn undead.