Ian Watson's first novel, published in 1973, was one of his best, and an acknowledged classic of science fiction. Its theme is not a traditional sf topic, but a very intellectually challenging one: language as the means to bridge the gap between human consciousness and the otherness of the objective world. In Watson's fictional "embededed" language of the Xemahoas, a Brazilian Indian tribe, "This-Reality" is converted into the transcendent pattern of "Other-Reality," which is the world of pure being. The Sp'thra (who represent the essential otherness of the objective world, everything about it that we do not understand) bargain for the brains of speakers of this language, which they desire to learn. At the end, the main character experiences a breakdown of reality and a cognizance of a new state of being, reminiscent of such occurrences in the work of Philip K. Dick.