Treatise is a set of interlocking geometric shapes, with a central straight line running through them, which generally serves as a reference point throughout the score. The instrumentation and the number of performers are free. The idea is to establish relationships between the graphic forms and the performance. There are no predefined rules; each group of performers establishes its own relationships and translates them musically. In this way, Cardew hopes to attract what he calls the “musical innocents,” who he believes will give the best performances of the work.

The score is very rich and inspires many musicians. Treatise is a real musical success and makes Cardew a very influential composer. In 1966, Morton Feldman said of him: “Whatever direction music may take in England, it can only emerge from Cardew, because of him, thanks to him. If the new ideas about music can be seen as a movement in England today, it is because he stands as a moral force, a moral center.”

Nevertheless, Treatise also symbolizes a failure for Cardew. Indeed, the best versions are played not by novices but by solid musicians, both experienced in contemporary musical practices and in graphism. His questioning of classical notation in favor of graphic notation did not solve the problem of accessibility. Experimental music is still reserved for an elite, of which he is now one of the leaders.