Opera librettists are modest types. This is mainly because they are forced to be: operas are, after all, all about the composers. Mention The Marriage of Figaro, and most people will think of Mozart. Few will remember Pierre Beaumarchais, who wrote the play that the opera is based on, and almost no one will be able to name Mozart’s librettist, Lorenzo Da Ponte.

This junior position isn’t necessarily cause for complaint – librettists know well that that the composer is taking on the bulk of the work. But I’ve sometimes been shocked by how dismissive the music world can be about libretti.

Collaborations are as various as artists are, and texts for contemporary operas are generated from all sorts of sources. In the various collaborations I’ve been involved with – to date, seven libretti for four different composers – the words have always been written first. And in this sort of collaboration, the composer depends on me to create the ideas and the structures which will inform and support his or her work.

Most importantly, a libretto is a text written for performance. Opera isn’t a concert with costumes and movement: it is a work of theatre. A good libretto will create...