The use of existing music in new works is a widespread practice in recent art music, considering the number of “recompositions” that have been written since the late Eighties, and their remarkable variety in techniques, style and aesthetics. Nevertheless, essays on specific works have been published but no systematic musicological research has been undertaken on this phenomenon. The aim of this thesis is therefore to investigate musical borrowing in late twentieth- and early twenty-first-century Western art music both from a theoretical and a practical perspective. In the first part, different approaches to the study of musical borrowing by Burkholder, Straus, Metzer and Watkins are reviewed, with particular emphasis on methods and epistemological frameworks. Part two then broadens to include literary, semiotic and philosophical knowledge on the subject, with reference to theories of Genette, Eco, Steiner and Gadamer. Finally, part three consists of a multiple case-study of eight works composed by several authors between 1990 and 2013 using Gesualdo’s music (i.e. Adolphe, Dean, Eötvös, Francesconi, Haas, Mantovani, Ronchetti, Sciarrino). The results of this in-depth analysis show that a comparative study on musical borrowing as a creative interaction with tradition not only can provide a valuable improvement of our knowledge on individual authors but also can advance our understanding of the current condition of Western art music.