Arthur Symons 
The Symbolist Movement in Literature [EPUB ebook] 

The Symbolist Movement in Literature is a highly influential work of criticism and served to introduce the French Symbolists to an Anglophone readership. This work had a formative influence on modernist writers such as Joyce, Eliot, Pound and Yeats, helping to shape the role of the Image in modernist writing.
Without symbolism there can be no literature; indeed, not even language. Symbolism in literature really is a form of expression, at the best but approximate, essentially but arbitrary, until it has obtained the force of a convention, for an unseen reality apprehended by the consciousness.