William Bolcom — American Composer born on May 26, 1938,

William Elden Bolcom is an American composer and pianist. He has received the Pulitzer Prize, the National Medal of Arts, two Grammy Awards, the Detroit Music Award and was named 2007 Composer of the Year by Musical America. Bolcom taught composition at the University of Michigan from 1973–2008. He is married to mezzo-soprano Joan Morris... (wikipedia)

And once I know what the first page is, then the rest will come.
I would find myself, not necessarily always assigning these little bits of music for here or there, but all of a sudden something would fall into place and it would be exactly that.
Now the big question is if you are going to go to all the trouble of setting an opera and making all that music and so on, there's got to be some aspect that you can do in an opera that really makes it worth while.
There's got to be something that you can do that will not just be a nice honor to the play, or the book, or the movie you're dealing with, but some aspect that maybe can explore something that the play couldn't do.