I guess to make it more clear:
Ranger, Paladin, Monk, and Barbarian are but Subsets of Fighter/Warrior
Druid and to some extent Paladin are subsets of the Cleric
Enchanters, Necomancers, Illusionists, Sorcerors, and Psions are all subsets of the Wizard
Ninja, assassin, swashbuckler, and Bard are...