Yo-Yo Ma is the most popular classical musician in the world, at least according to sales figures. But unlike most of the other musicians at the top of that particular list, Ma is neither a gimmicky tenor nor a barely-clothed, barely-classical string quartet. In fact, Yo-Yo Ma may have the answer to the long-pondered question of whether classical music can truly appeal to a mass audience in today’s pop-culture-obsessed world. “A musician needs to know one tradition deeply, to know one room in the mansion of music. And then he needs to have the skill to be able to work with musicians from other traditions – it’s a question of transferability… Working in different musical worlds opens up new areas of expression.”