DeSales Harrison 
End of the Mind [PDF ebook] 
The Edge of Intelligibility in Hardy, Stevens, Larkin, Plath, and Gluck

This book seeks to include among accounts of modern lyric poetry a theory of the poem’s relation to the unintelligible. De Sales Harrison draws a distinction between sites of unintelligibility and sights of difficulty; while much has been said about modernist difficulty, little has been said about the attention that poets give to phenomena that arrest, impede, obscure, damage or destroy the capacity for intelligible representation.