The doctoral dissertation is a monograph of the life and artistic work of Julian Fontana – a truly Renaissance mind, a pianist and composer, an émigré activist, translator, language purist, author of scientific studies of astronomy, and the closest friend, pupil, copist and advisor of Fryderyk Chopin, who went down in the history of music thanks to his acting as the editor of his OEuvres Posthumes. It represents a type of contextual biography in which Fontana is presented against the background of Chopin's life, Polish émigré community, and the era, depicting the existence of not only Fontana himself, but also a nineteenth-century artist facing socio-economic and cultural changes. Furthermore, the thesis presents new factual data on Chopin himself, constituting a contribution to completing the composer's biography. The monograph comprises six main Chapters: I –Sources, II – Life, III – Musical Output, IV – Pianism, V – Fontana – Copyist and Editor, VI – Appendices, and a Bibliography.