"A fleet of starships comprised of Masters and Celestial Beings from numerous galaxies and ruled by the Ascended Masters of the Great White Brotherhood (White meaning White Light)), who are helping Earth enter the Age of Aquarius. They travel the Universes and have the capability to influence and direct God's plan for continued evolution. They are highly advanced beings who do not necessarily appear in a third dimensional form. They have assisted Earth in its evolutionary path since the beginning." (SJA)
See also Ashtar Command for more information, and for an alleged list of members.