This paper introduces the IASPM Journal special edition entitled Twenty-First Century Popular Music Studies (PMS), in which a number of papers respond to Philip Tagg’s paper “Caught on the Back Foot: Epistemic Inertia and Visible Music” (2011). Respondents discuss a lack of ethnographic methodology in three prominent journals, Popular Music, Popular Music and Society and Journal of Popular Music Studies; the success of PMS in Australasia and the role of ethnomusicology there; the potential of ecomusicology for PMS; the proliferation of PMS courses in new universities in the UK; gender and sexuality within PMS; differences between the concepts of invisible and of ubiquitous music; and the need for addressing corporeality within PMS. The common threads of these discussions are brought out, and a number of key issues emerge. Interdisciplinarity is emphasized and the interactions of classical and popular music, ethnomusicology as well as recording and production are examined. It is suggested that PMS might consider tactical alignments with other relevant bodies in order to overcome epistemic inertia, including ethnomusicology organisations, the Association for the Study of the Art of Record Production, and academics and practitioners involved in teaching and making popular music.