The corpus of literature on street performers and street culture can be conveniently, though not neatly, arranged into literature that concentrates on the documentation, illustration and transcription of street sounds; instruments, bands, parades, opera and their audiences; aesthetics and politics of space; regulation and the law and advocacy. Studies of street culture often pass over or marginalise the rich soundscapes of streets. In the cases of the Cantonese opera in Hong Kong and Bach in Subways, performers transform public spaces into performative spaces, a sometimes awkward transition, as has been theorised in a large body of literature including by Cohen and Simpson. Street performers, like street merchants and shopkeepers, have been regulated for centuries with both positive and negative consequences in such countries as Australia, Brazil and the United Kingdom. Journalists, local authorities and advocacy groups are also often supporters of social and cultural change.