Software mediates a great deal of human musical activity. The writing, running, and maintenance of code lies at the heart of such software. Code Musicology: From Hardwired to Software argues why it is time for a “code musicology,” then outlines what that should entail. A code musicology opens a conduit between musicology and software studies, providing insights into both of these now interlinked fields along the way. It extends an ethnomusicology of technoculture from the world of hardware and the hardwired to software, code, and algorithms. For popular music studies, it helps direct attention to a newly relevant industrial focus—IT and software-centered transnational commerce—as a result of sectorial transformation. Denis Crowdy demonstrates how analysis from software studies, critical code studies, and the digital humanities offers insights into power relations, diversity, and commerce in music. Crowdy weaves readings of code and application programming interfaces (APIs) into the discussion, as well as ethnomusicological fieldwork exploring music and mobile phones from the Global South. Analysis of the author’s own music apps and associated distribution infrastructure provides unique insights into the machinations of music “appification.”