So at this year's London Book Fair I was invited to moderate a panel to discuss this very question. Joining me were David Bradley, the editor and chief of SFX and Total Film magazines and Rosie Fletcher, the editor of Total Film. It was a lively discussion and the audience seemed to enjoy it but it did get me thinking. What is this 'mainstream'? Is it an invite-only club? What do you have to do to get this collective's attention? And is this 'mainstream' welcoming to genre or do they shun it?