Ramstad, captain of the al-Buraq, a rare space ship capabale of Alarf drive, causes an intergalactic incident by stealing a sacred egg-shaped artifact from the Tolt. What he takes is the glyph; a mysterious life form which communicates with Ramstad through telepathy.
Ramstad finds himself in a cat and mouse race against time as both his own leaders and the Tolt want the object (and peace) returned. However, there is more at play, as an all devouring force known as the Bolg is destroying sentient life throughout the universe. Ramstad with the help of the mystical Vwoordha must stop it before it is too late.
Farmer's highly descriptive narrative, which borrows concepts and symbols from Arabic culture and religion, draws many strange and wonderful pictures and is somewhat refreshing in a genre filled with western motifs, adding even more mystical intrigue to his already wondrous universe.
The Unreasoning Mask is extremely complex and can be difficult to follow at times, almost to the point of being more metaphysical discussion than space adventure. However it does pack enough punch, with a "must-know-how-it-ends" plot, that it is enjoyable enough as an action/adventure story set in space.