Répétiteurs are so much more than just pianists. Sure, they have to be able to get around the keyboard. But they also have to be able to read the multiple lines of a full score, coach singers, take the role of an orchestra and, in a nutshell, know the opera they are rehearsing probably better than anyone else involved in the process. And those are just some of the musical skills. Because a répétiteur must also be at once musically self-effacing, a linguist and a diplomat who can accommodate and reconcile the often conflicting demands of singers, conductors and directors. But, despite all that, there's no first-night curtain call for this vital figure.