In common with the other performing arts (dance and drama) music can properly exist only when it is performed; the performer’s task is to communicate the creator’s message to an audience as effectively as possible. Dancers and actors, however, use their bodies more directly than do most musical performers who (unless they are singers) also have to cope with an extraneous instrument (the piano, violin, trumpet, etc.) which can form an extra barrier between composer and listener. This extra problem for the instrumentalist may result in the feeling that there are great physical obstacles to overcome, and this in turn often leads to an undue emphasis on acquiring a strong technique through mechanical practice. Many indeed are the books of exercises written for this purpose in the case of the piano, for example.