William Empson is now best known for his literary criticism, and in particular his analysis of the use of language in poetical works, and although his own poetry is of a very high order indeed, yet it seems to be undervalued. In his critical work he was particularly influenced by the philosopher Ludwig Wittgenstein, whose own work is largely concerned with the problematics of language in expressing thought with clarity. His best known work is the book Seven Types of Ambiguity. This book was to have a significant impact on the 'New Criticism' movement, a school of critical theory which directed particular attention to the text itself, among whose adherents may be numbered F R Leavis.
His critique of Milton and Puritanism in Milton's God was a savage and sustained attack on Christianity and the puritan ethos.
His poetry is clever, dry and aethereal: his high regard for the metaphysical poet John Donne is to be seen in many places within his work, tempered with his appreciation of Buddhist thinking, and his occasional tendency to satire.