The aim of the thesis is to promote understanding of the published concert arrangements of Leopold Godowsky (1870-1938). This may be attained by elucidating them in three ways. The historical approach sets the arrangements in the context of those by Liszt, Rachmaninov, Busoni, and others. The analytical considers technical matters to do with harmony and counterpoint, rhythm, structure, and key. But the latter mode of inquiry is unable to rise to the challenges posed by the wider concept of arrangement; for this reason, the Introduction debates aesthetic matters, and in the process attempts to explicate Godowsky's syncretic commitment to an unfashionable cause. The broader musical argument is waged not chronologically but in terms of the various post-opera-fantasy 'genres' of arrangement that Godowsky explored. Each Part, though, compares and contrasts Godowsky's earlier and later forays into the various 'genres'. Part One examines the Chopin arrangements. The musical inquiry is here supplemented by accounts of the historical context, genesis, chronology, and critical reception of the fifty-three studies on Chopin's etudes (1894-1914). Part Two deals with the two collections of Baroque arrangements. The musical inquiry has a dual mission: to indicate the paraphrase qualities of the earlier collection, Renaissance (1906 and 1909), and to judge the extent to which the later 'elaborations' of Bach's solo violin and cello suites (1924) 'realise' and recompose the originals. Part Three scrutinises the 'symphonic metamorphoses' on Johann Strauss (ca. 1905-07 and 1928), the twelve Schubert song arrangements (1926), and the reworkings of Weber, Albeniz, and others. The Conclusion remarks on the fate of the 'genres' with which Godowsky engaged and briefly charts the trajectory of the arrangement after Godowsky. In highlighting the rigidity of Godowsky's idiom, and in evaluating the merit of the particular arrangements, it isolates various components of Godowsky's musical enginery: for instance, 'discretion' and 'naivety'. One trend in Godowsky's output, though, is discernible. The earlier arrangements are generally more radical; for they thoroughly rework the details of the original texts. By contrast, the later ones tend to perform only cosmetic surgery on the originals.