The most significant language created by Barker for his setting is Tsolyáni, which resembles Urdu, Pushti and Mayan. Tsolyáni has had grammatical guides, dictionaries, and even a complete language course developed for it. In order for his imaginary languages to have this type of depth, Barker developed entire cultures, histories, dress fashions, architectural styles, weapons, armor, tactical styles, legal codes, demographics and more, inspired by Indian, Middle Eastern, Egyptian and Meso-American Mythology in contrast to the majority of such fantasy settings, which draw primarily on European mythologies.
Tékumel was severed from interplanetary trade routes and went through a massive gravitic upheaval which threw civilization into chaos, when it passed into a 'dimensional pocket', possibly as the result of hostile action. The native species broke loose from their reservations and civil war seized the planet. Several other significant changes took place due to the crisis: mankind discovered it could now tap into magical forces, the stars were gone from the sky, dimensional nexi were uncovered and pacts with “demons” (dimensional travelers) were made and a complex pantheon of gods discovered. Science began to stagnate, the belief that the universe was understandable slowly faded, and a Time of Darkness descended over the planet.
Much of Barker's writing concerns the time when civilization on Tékumel is rebuilding itself from a state of primitive barbarism and focuses particularly on the Five Empires which control much of the world's northern continent.
In 1975, Tactical Studies Rules, Inc., the publishers of Dungeons & Dragons, published the Tékumel setting as a standalone game under the title of The Empire of the Petal Throne (a synonym for the Tsolyánu Empire). It brought a level of detail and quality to the Campaign setting which had previously been unknown in the RPG industry, and could be considered a turning point away from the tactical roots of RPGs. The game was the subject of articles in early issues of Dragon Magazine, but factors including inconsistent support from TSR led to its decline in popularity. Over the subsequent thirty years several new games based on the Tékumel setting were published, but to date none have met with commercial success.
In 1984, DAW Books published Barker's Tékumel novel The Man of Gold. This was followed by Flamesong in 1985. In 2003, Zottola Publishing published three additional novels: Prince of Skulls, Lords of Tsamra, and Death of Kings. Zottola re-released the two earlier novels in 2005.