The purpose of this book is to shed light on the rather unexplored «English facet» of Fernando Pessoa, considered one of the major Portuguese poets of the twentieth century. The originality of this study also lies in its extensive use of unpublished documents. Out of the bulk of Pessoa's English writings, The Mad Fiddler has been selected; it offers not only poems of better quality than most of his writings in English but it also has the advantage of being a complete and coherent suite of «mystical» poems. A systematic comparative study of the themes in The Mad Fiddler and in the poems by the four Portuguese heteronyms reveals a clear continuity and shows that Pessoa's bilingual Poetry is based on his main ontological quest, which he tried to solve by means of his dramatic scattering into «masks». After this comparative analysis, the individuality of The Mad Fiddler is defined. Following an overwiew of the unpublished English writings found in the Pessoan legacy, The Mad Fiddler is analysed by means of Pessoa's own unpublished comments. An investigation of Pessoa's private French library and of his unpublished Literary Appreciations proves how fully he understood the impact of Symbolism on the evolution of Modern Art. The Mad Fiddler could indeed be viewed as an English echo of Pessoa's interest in modern trends in Literature and as a kind of «English microcosm» of gessoa's aesthetic theory.