In the era of the never-ending playlist, when tunes are almost too algorithmically available, these writers remind that a regular appointment of conscious listening, playing or singing can be better than a visit to the clinic.

Listening to Edith Piaf in Oppert’s presence, a 65-year-old man with A.L.S., a former boxer, removes his oxygen mask to sing along and proclaim: “I’m in the ring. I’m strong enough to fight!”

Of course Schubert might not be the right prescription, and finding the proper dose takes experimentation. Why is it that one Bach suite calms a teenager with severe autism, while another incites him to punch a hole through her cello?