What is it to write 'new' music? Music is not written in a vacuum, and Op. 48 investigates how one small Bach piece's (re)sourcefulness can result in a variety of musics. The collection (of 48 pieces) explores not only scientific areas of musicology and analysis, but subjective and intuitive areas of performance, resonances with other art forms and more fantastical elements such as virtual history and humour. More challengingly, the amount of music (some 2 hours) presents an issue over the language used in discourse, for the linearity of words is partial and even misleading. Op. 48 is a criticism of what Bach notated and an economic way of talking about how music talks. Drawing on poetic and philosophic insights, 'Bach' is played with re-creatively: the precedents and parallel developments of the procedures I employ form a further stage of possible development. Rather than repeating empty encomia in this Bach Festschrift, Op. 48 honours Bach's invention by creating further music. Op. 48 is arguably not subservient to the Bach, and asks when (if ever) pieces grow up and become independent organisms. For while Op. 48 exhibits a wide-ranging diversity, it does not (and perhaps cannot) claim to be exhaustive, since the music seeds further pieces, which questions if it is viable to talk of an art work as discrete at all.