Like so many of Tom Raworth’s poems, ‘Caller’ (Caller and other pieces, Edge Books, 2007) has no apparent propositional or argumentative form. Its beginning, middle, and end are not marked by shifts of intensity, or crises and resolutions. The title has no fixed referent: it could be to do with Bingo or visiting or square-dancing or old-fashioned telephone exchanges; or maybe it’s best just to rely on the general OED definition of ‘a person who cries aloud, proclaims, or announces; (hence) a person who invokes, summons, or exhorts by calling aloud. Also: an animal which makes its characteristic call. Also fig.’ It’s certainly a characteristic call of Raworth’s poems to proclaim and announce, to invoke and to summon. But usually not to do so with any sustained object. So whatever may be invoked in the course of the poem – and an awful lot of things are – it won’t be there a moment later. Not in the poem, at any rate. It will be there in some vestigial or creeping form in the mind of the reader or listener, but tessellated with so many others it will be constantly being reshaped and repurposed and reconnected. These poems always move very quickly. If we had the right nanotechnology and could send tiny investigative machines into a Raworth poem, we would find thousands of minute potential poems interacting inside them faster than the speed of synaptic connections. Like a speeded-up film of an ant colony, only with words instead of ants, and with the words liable to mutate unpredictably ...