First published in 1962, this book reveals unexpected complexity or equivocation in Wordsworth's use of certain key words, particularly 'image', 'form' and 'shape'. The author endeavours to show that this complexity is related to the poet's awareness of the ambiguity of the perceptual process. Numerous passages from The Prelude and other poems are analysed to illustrate the argument and to show that, because of this doubt or hidden perplexity, Wordsworth's poetry has a far richer texture, is more concentrated, intricately organised and loaded with ambivalent meanings than it would otherwise have been. New light is also shed on Wordsworth's debt to Akenside.