[Image description: A young Joan Didion sits with her daughter, Quintana Roo Dunne, on her lap. Didion’s hand is in her daughter’s hair.] Toward the end of the sole biography of Assia Wevill, a person history knows best as the woman who troubled Sylvia Plath’s marriage to Ted Hughes, the writers Yehuda Koren and Eilat Negev engage in a grim comparison. Like Plath, Wevill took her own life, but it was a murder-suicide; she also killed her four-year-old daughter, Shura, when she gassed herself in March 1969. Comparative discussions of both women’s suicides have abounded since the poet Robin Morgan first wrote publicly about Wevill and Shura’s deaths in her 1973 poem “Arraignment,” but Koren and Negev go a step further. Quoting Professor Anita Helle, a Plath scholar who has the odd distinction of also being Sylvia’s cousin, they describe Plath’s “desertion” of her children as an act of extreme cruelty, one somehow worse than Wevill’s murder of her toddler.