Sarah Ruhl’s Letters from Max, a ritual, is an adaptation of her 2018 epistolary book Letters from Max: A Poet, a Teacher, a Friendship, which included letters between Ruhl and Max Ritvo, her playwriting student and, shortly thereafter, friend. Ritvo died at age 25, of a recurrence of Ewing’s sarcoma, a pediatric cancer first diagnosed when he was 16. He graduated from college while undergoing chemotherapy and surgeries, producing poetry and plays and music along the way, becoming a teacher to Ruhl as much as she was to him.