The poetics of The Promises of Glass capitalizes on the absences effected in the composition of glass. A fusion of sand, soda, and potash, its peculiarity resides in how these elements are not perceived but effaced. Glass sublimates its ingredients into a unity that displaces them; the differences comprising glass are erased so glass may appear. “Isn’t there another story / consistent with sand?” Palmer asks, “How it turns to mirror-glass / when heated in your hand[?]” Glass retains no visible residue of its particles, since they would obstruct its clarity: there is a poeisis, then, of withholding. Yet glass, in turn, itself withdraws. It might hide in the form of a window, to facilitate transparency or translucence, or it might withdraw into a mirror, to enable an opacity permitting reflection. Glass promises to withdraw into an invisibility that allows one either to detect an object or light, or else to see oneself. But what one must not see is the glass itself.