Luna happily hands one over.
Warrior
Stat Alignment: Fitness / Ardor
A physical fighter who focuses on melee weapons and overwhelming damage.
Ranger
Stat Alignment: Grace / Ardor
A physical fighter who focuses on ranged weapons and precision, with bonuses to taming monsters.
Mage
Stat Alignment: Sanity / Ardor
A brute-force spellcaster focused on destructive force from long range, with bonuses to casting speed.
Monk
Stat Alignment: Fitness / Moxie
A physical fighter who focuses on martial arts and overwhelming speed.
Rogue
Stat Alignment: Grace / Moxie
An agile fighter with bonuses to stealth.
Druid
Stat Alignment: Sanity / Moxie
A balanced spellcaster focused on terrain control and utility magic, with bonuses to enduring hostile environments.
Shaman
Stat Alignment: Fitness / Allure
A melee spellcaster focused on enhancement and impairment magic with bonuses against other magic.
Warlock
Stat Alignment: Grace / Allure
A balanced spellcaster focused on control and illusions, with bonuses to summoning.
Cleric
Stat Alignment: Sanity / Allure
A brute-force spellcaster focused on healing and restoration at close range, and battlefield support at long range.
No Class - Adventurer
Stat Alignment: None
The gist is thus: Each class gains a special bonus from two of the six stats. To unlock a class, he has to have at least one of those stats above 10, so Warrior is the only class he doesn't have access to. Adventurer, unlike the rest, has no requirements and no stat bonuses.
The first nine classes come with a free level-up to level 1, as well as two free stat points, one free skill point, and auto-unlocks a sequence of core class Skills.
The Adventurer class gets none of those benefits, but does have the unique ability to unlock any skill that is performed in front of them. For the other nine classes, unlocking a skill requires already having purchased the prerequisite skill as well as having some inkling of how to perform a skill without system assistance.