“You know, I think as I get older,” Joan Baez tells David Remnick, “someone will show me a photograph”—of the March on Washington, for example—“and I’ll think, ‘Oh my god, I was there. And those people were there, and Dr. King said what he said.’ Sometimes, going into a historic moment, you know it, and other times you don’t know it. In that case I think by midway through the morning, we all knew.” Baez became the defining voice of folk music as it intersected with the leftist politics of the sixties and beyond. She performed at the March on Washington and at Woodstock; she went on a peace mission to Hanoi where she was caught in an American bombing raid; she adopted cause after cause. Her work has changed with her age. She can’t hit the high notes of her youth, and she stopped writing songs decades ago—or as she describes it, the songs simply stopped coming to her. Yet she has never stopped performing protest music. At WNYC’s studios, she played two songs from her new record, “Whistle Down the Wind”: one is a prayer for healing after the mass killing in Charleston, written by Zoe Mulford; the other a dirge on climate change by Anohni.