But while Tillman admires aspects of her mother’s personality, she mostly feels the ambivalence of her book’s subtitle. Tillman does not love her mother — she writes candidly that she hasn’t since the age of 6 — but she doesn’t want her to die. She is therefore bound to help her live. “I performed the good daughter,” she writes. “My heart wasn’t in it, my conscience was.” The sangfroid is striking and refreshing, even uncanny at times. (It is also the predominant tone found in Tillman’s fiction, cut with mordant humor.) There is no breathless rendition of the cruelty of disease, or the pain of a loss that drags on over a decade. Sophie’s illness presents as a medical mystery at first, but the chronicle of her health has no narrative momentum. Instead, Tillman seems more curious about the strange condition her mother suffers from, offering diagrams of the working of brain shunts and the contraption’s medical history, signaling an intellectual remove from the circumstances in which she finds herself.