In 2012, the novelist Yiyun Li twice tried to take her own life. She wrote of the experience in “Dear Friend, From My Life I Write to You in Your Life,” a series of enigmatic essays in which she traced her depression and lifelong desire to disappear. “You should be very careful every day for the rest of your life,” she recalled a doctor warning her. “Things could sneak up on you.”

There was no subtle creep of sadness to watch for, however. What happened was blunt and nightmarish. Months after the book was published, in 2017, Li’s 16-year-old son killed himself.

In the months after his death, Li began writing a new novel. “Where Reasons End” imagines a dialogue between a mother and her teenage son after he has been lost to suicide. It is aloof, angular and idiosyncratic, as Li’s personal pieces tend to be; her previous novels, like “The Vagrants” and “Kinder Than Solitude,” in contrast, are more conventional, majestically bleak portraits, often of the Communist China of her childhood.

Li’s characters share the credo from a Marianne Moore poem that “the deepest feeling always shows itself in silence; / not in silence, but restraint.” (As a writer, Li has an avowed phobia of using the word “I” — too melodramatic, she says.) Mother and son in this novel rarely openly grieve. There is no rage or accusation; the question of why he killed himself is never explicitly raised, although the mother suspects it lies in his harsh perfectionism:

“Who, my dear child, has taken the word lovable out of your dictionary and mine, and replaced it with perfect?