One Shabbat, toward the end of the morning service, Tova Mirvis was stricken by a debilitating headache, in which “the pain concentrated along the line where my hat met my head.” She rushed from the synagogue, entertaining worst-case scenarios: Was this, perhaps, a brain tumor or an aneurysm? But once she stepped outside and removed her hat, the pain subsided.

This dramatic scene is just one instance in The Book of Separation, a graceful and deeply affecting memoir by an author of three novels, in which Mirvis’s struggles with Orthodox Judaism and an increasingly unhappy marriage began to manifest physically, as if her body were sending distress signals to her more-cautious brain.

Chronicles of leaving Orthodoxy have been plentiful during the past few years, informally referred to as “Ex-Frum” or “Off the Derech” memoirs. Among the more notable books are Shulem Deen’s All Who Go Do Not Return, which won a 2015 National Jewish Book Award, and the best-selling Unorthodox, by Deborah Feldman. With this latest contribution, Mirvis applies her novelist’s flair to what might otherwise be a narrative familiar to anyone who has wrestled with religious doubt, endured a troubled marriage—or simply felt trapped.