Human (PHB)

Although humans are treated as a single race in the AD&D game, they come in all the varieties we know on Earth. A human PC can have whatever racial characteristics the DM allows.
Humans have only one special ability: They can be of any character class and rise to any level in any class. Other PC races have limited choices in these areas.
Humans are also more social and tolerant than most other races, accepting the company of elves, dwarves, and the like with noticeably less complaint.
Because of these abilities and tendencies, humans have become significant powers within the world and often rule empires that other races (because of their racial tendencies) would find difficult to manage.