 He was a founding member of the Society for Creative Anachronism (SCA) in 1966 and of the Swordsmen and Sorcerers' Guild of America (SAGA), also in the mid-1960s.The latter was a loose-knit group of Heroic Fantasy authors led by Lin Carter, originally eight in number, with entry by credentials as a fantasy writer alone.Anderson was the sixth President of Science Fiction and Fantasy Writers of America, taking office in 1972.