Most of us are familiar with the notion of writer’s block, that paralysis of invention induced by the appalling sight of a blank page. Composer’s block is less widely discussed, although musicians seem equally afflicted by creative drought. Perhaps the best known case is that of the Russian composer Sergei Rachmaninov, the subject of Radio 3’s Sunday Feature, which describes how the great man finally fought his way out of a numbing three-year ‘apathy’ with the help of a hypnotist.