A study of Guilln's critical work through a comparative analysis of Lenguaje y poesa essays concerning the mystic poetry of saint John of the Cross and the visionary lyrics of G.A. Bcquer.The obscure difficulties of these poets challenge Guilln's vision of literature as a conscious art of language.Symbolic interpretation requires the use of different strategies, basically a philological approach and the methods of several new criticisms stemming from the Romantic hermeneutics, concerning problems such as the alternance of litteral and spiritual senses, the poem as an imaginative transgression of linguistic norm, or the shifts between textual and intentional messages.Guilln's answer to the question of unintelligibility leads to a consideration of the way in which texts are determined and the borders between poetry and literary criticism.