Lucy Green's (2008) "Music, Informal Learning, and the School: A New Classroom Pedagogy" gives rise to an interesting corollary. Does the manner of music's transmission inform one's understanding of a musical category? While categories of music can be difficult to define according to strict musical characteristics, a better understanding of musical transmission--of how a music is passed on and learned--may provide insight into the nature of a musical category itself. Green's work, which associates informal learning with popular music practice, presents this possibility. Such an understanding offers potential for music educators and students to become increasingly clear about what and how they are teaching and learning. This essay uses the jazz tradition as a means of exploring the understanding of a musical category through its modes of transmission. The jazz tradition has synergies with Green's research because it is a music that has made the transition from informal to formal realms of learning. This essay proposes that jazz and popular music can be linked through pedagogy by highlighting their shared cultural origins and overlapping communities in ways that further inform the idea of category as a pedagogically-driven construct. The author begins with a brief examination of how jazz was transmitted prior to its formalization. The modes of transmission employed by Green (developed through her study of popular musicians) are similar to modes of transmission utilized by jazz musicians prior to Jazz Education. In showing these similarities, the author focuses on select musicians who have emerged as skilled and valuable jazz practitioners prior to the advent of Jazz Education. (Contains 27 notes.)