The dwarf first appears as a player character race in the original 1974 edition of "Dungeons & Dragons", with a design that is strongly influenced by the dwarves of Poul Anderson's 1961 novel "Three Hearts and Three Lions". This early version of the "D&D" dwarf is limited to playing a fighter, and can not progress beyond the sixth level. With the release of the first supplement, Greyhawk, in 1976, they were then allowed to play a thief with no level restriction. The dwarf and other non-human characters are considered their own classes in the original "Dungeons & Dragons Basic Set" (1977) and its sequels, where they were only permitted a maximum level of 12 (compared to the Halfling's 8, the Elves' 10, and the human classes 36). With the arrival of "Advanced Dungeons & Dragons", the dwarf was returned to a player character race in the "Player's Handbook" (1978) and detailed as a monster in the original "Monster Manual" (1977). A number of dwarven subraces are presented as character races in the original "Unearthed Arcana" (1985).