What, one wonders, will John Eliot Gardiner be chiefly remembered for? Perhaps, by many who have worked with him, for his notorious rudeness to performers and colleagues. At one point in his marvellous new book on Bach he refers to the master ‘losing his rag with musicians’ (as a corrective to the ‘Godlike image’ of Bach that posterity has tended to prefer), and one senses a not entirely veiled sympathy: one struggling director excusing another, admittedly greater, but in that respect at least no different.