While at Berkeley, Barker had not set aside his world creation project. Indeed, despite stepping back from an active role in
science fiction fandom, he had commenced "proto-gaming" with a group of like-minded science fiction fans including fellow linguist
Bill Shipley and Victor Golla, producing elaborate documents to support the exploration of that shared world. Having watched the
Dungeons & Dragons games started by Mike Mornard, one of the original testers for D&D, when Mornard moved to Minneapolis from
Lake Geneva, Wisconsin, Barker resolved to create his own ruleset based on his own created world and the game mechanics from D&D. After six weeks, this was self-published in August 1974 as
Empire of the Petal Throne and play commenced forthwith, including such occasional members as
Dave Arneson – who singled out Barker and Tékumel as being his favorite
Dungeon Master and roleplaying game, respectively – from early days. Once
Gary Gygax's attention had been drawn to Barker's work, it was decided that
TSR would publish a revised version of the game mechanics along with a condensed version of his
campaign setting.
Empire of the Petal Throne was published by TSR in August 1975 for
Gen Con VIII, making it the third role-playing game from TSR. In a December 1976 editorial for
The Dragon magazine, editor Tim Kask drew comparisons between the world of Tékumel and
J. R. R. Tolkien's
Middle-earth not in terms of literature created, nor that his work was derivative of Tolkien's, but rather regarding the in-depth detail in the setting, mythos and linguistic backgrounds and concluded that "In terms of development of detail, I think EPT [Empire of the Petal Throne] has it over Middle Earth in the matters that most concern gamers". Barker disliked the limited support TSR gave to the setting, and after 1977 he took his Tékumel setting back from TSR and ultimately brought it from one publisher to another: Imperium Publishing (1978),
Adventure Games (1981),
Gamescience (1983–1984), Tékumel Games (1983–1986),
Different Worlds Publications (1987–1988), TOME (1991–1994), Tita's House of Games (1997–2002), Zottola Publishing (2002–2003), and
Guardians of Order (2005). Despite having had a head start on other in-depth campaign settings and seeing his game released no less than four times with various supplements and magazine articles, many of which he contributed to, and having authored five books using the same setting, Barker's Tékumel in both roleplaying and literary domains is still well known to only a relatively small audience, leading German magazine
Der Spiegel in 2009 to publish an article on Barker's life entitled "" ("The forgotten Tolkien"). The article quotes friends and acquaintances who posit that this may be, at least in part, due to the unfamiliarity of the setting compared with Western society, echoing Fine's observations from 1983, and possibly even that Tékumel was released to the gaming world too early on, when players had only just started to experiment with their own invented worlds rather than fitting their play into preconfigured, non-literary domains with novel backgrounds. ==''Serpent's Walk'' and Holocaust denial==