The poems [in Frequencies] have become a cumulative succession of brief, intense engagements between need and silence; again and again they attempt an imaginative synthesis of "the interior / that calls", "the verbal hunger / for the thing in itself" and "untenanted space", "the darkness between stars".

As for Eliot, whose "vacant interstellar spaces" R. S. Thomas's universe recalls, "each venture is a new beginning" and a central theme of Frequencies is the inadequacy and failure of vocabularies….

Frequencies is a profound collection with a beautiful gravity of utterance capable of absorbing its intermittent lapses into portentousness and abstraction. R. S. Thomas's strength has always been in his deployment of metaphor, and when he relies on plain statements of position he can teeter on the brink of the absurd…. As always there is a suspicion that some of the characteristic neat encapsulations come a trifle too easily ("time's face", "the mind's shelf", "the mind's tools", etc. though there are far fewer of them than in the earlier work), and there is also the sermonizing tendency to point up analogies. In "Fishing", for example, although there is some marvellous imagery ("the hook gleams / the smooth face creases in an obscene / grin") it is cramped by an explanatory framework: "Often it seems it is for more than fish / that we seek." But these are small faults to set beside R. S. Thomas's power, at his best, to involve his reader, passionately, in the riddle of existence. Despite his own use of the word "confrontation", and although he is sometimes ready to storm at God "as Job stormed, with the eloquence / of the abused heart", his debate with "ultimate reality", which could so easily flounder in abstraction, is infinitely more complex than that:

                Face to face? Ah, no
                God; such language falsifies
                the relation. Not side by side,
                nor near you, nor anywhere
                in time and space….

and an apt emblem for the subtlety with which an unpara-phrasable meaning penetrates the fabric of many of these poems is that of the human mind seen as "a spider spinning its web / from its entrails … swinging / to and fro over an abysm / of blankness". In fact it comes as no surprise to find that this image is a redeployment of one which appeared in a poem, "The Listener in the Corner", from R. S. Thomas's previous volume The Way Of It. Increasingly, without seeming repetitious in any slack way, his figures appear to be becoming counters manipulated in a passionate game of definition. It is almost as if he were attempting to crack God's code by restricting his own, and it gives those poems where abstractions are kept to a minimum a remarkable and immediate metaphysical intensity.

There remains, of course, the question "where next?", since, in essence, Frequencies does not (cannot) go beyond Laboratories of the Spirit and The Way of It except in the brilliance of its refinement…. [With] a poet as important and exciting as R. S. Thomas there is always a particularly keen sense of anticipation. One knows that he will go on asking the same fundamental questions, because he is a writer incapable of trivia, but the shape they take as poetry may still—judging by his present power—hold even greater surprises than when Iago Prytherch vacated the stage for God.