Contains parts for violin, viola, cello, and flute. (These parts are optional, but beautiful if you have. the people who can play them.) The Mass of Joy is a Catholic Mass setting for Christmas, Easter, and Ordinary Time. It was composed to be both simple to sing and beautiful to listen to. Using only a five-note scale in the key of E major, it will be singable for everyone, rather than just the music snobs, and even at 8:00 in the morning. Buy one copy and print as many as you need.