Some conductors conduct from the fingers — think of Gergiev’s convulsive gestures, flickering up and down the keyboard of an invisible piano in the air — while for others (check out footage of an elderly Richard Strauss) it all comes from the wrist: graceful, fluid and utterly detached. You could cut off Toscanini and poker-down-the-back-of-his-tail-coat Karajan (famously dismissed by fellow-conductor Fürtwangler as ‘just a time-beater’) at the waist and lose nothing from their precise gestures; but try the same trick with the irrepressible Dudamel or Kristjan Jarvi and the life-force of movements that start from the feet and shudder up...