Marilynne Robinson’s novels continue to demonstrate her utter mastery, and advance her to the very top rank of current novelists. She reigns over all others currently publishing in English. Her characters have more life and depth. Her themes flow from exalted planes, and her diction hews closely to the divine. In her latest, “Jack,” she explores the thoughts and impulses of Jack Boughton, a down-on-his-luck son of a preacher. Jack falls in love with a “colored” woman (the term used in...