Discussion of censorship mostly focuses on the spoken or written word, while censorship of art and music tends to be sidelined. In the field of music, probably the most controversial genre – and the one most censored worldwide – is heavy metal.

Heavy metal has some enthusiastic followers in the Middle East where it's also considered highly subversive and dangerous. A few years ago I wrote about the efforts to suppress it in Morocco and Egypt. 

Last August, the Saudi authorities broke up a concert at a compound in Riyadh and arrested "a group of Satan worshippers".

Today, Freemuse, an international organisation advocating freedom of expression for musicians and composers, has published a report: Headbanging Against Repressive Regimes.

You don't need to like heavy metal music to see its significance. Mark LeVine, the report's author, writes that underground genres of popular music "are avatars of change or struggles for greater social and political openness. They point out cracks in the facade of conformity that is crucial to keeping authoritarian or hierarchical and inegalitarian political systems in power." In China, for instance, metal "has become a bellwether for the contradictory processes of cultural and economic liberalisation coupled with entrenched authoritarian rule".

Although the report looks at the global picture, it has a substantial section on the Middle East, with case studies from Morocco, Egypt and Iran. Mark LeVine will be hosting discussions about it later today on Facebook and Skype.