This volume is an interpretation of the poetic work of one of the most important Spanish poets of the 20th century, Juan Ramón Jiménez (1881-1958). The lyrical production of this author covers the first half of the 20th century and develops from aestheticist fin de siècle poetry to abstract, quasi-religious writing at the end of his life. It is the intention to explain this evolution from the perspective of modern subjectivity, that is, by analysing the articulation of the lyrical subject that appears in Jiménez's poetic texts in the frame of the tradition of subject philosophy or philosophy of consciousness. A main presupposition underlying the present work is that, although each discourse develops within its own generic rules, literature and speculative thought hold an essential historical correlation with regard to, respectively, the representation and conceptualisation of human existence. Jiménez's poetry unfolds within the arch of modern poetry, from Romanticism to the Avant-Gardes, as it displays Romantic subjectivity, Symbolist textuality and Avant-Garde self-parody as different facets of the same paradigm. In this way, the present study can be considered the display of one long example that shows the how of modern subjectivity when exposed concretely, and thus as a sort of supplement to the many histories of Modernity that have appeared since Hegel and until today.