What is the theme in The Silent Woman: Sylvia Plath and Ted Hughes by Janet Malcolm?

Family ties is a theme. When a tragedy occurs in a family, its members often retreat together and use their energies to support one another. As often as not, the reputation that individual family members want to protect is their own. The tragedy that struck the Plath and Hughes families was the suicide of Sylvia Plath. Sylvia left behind her mother, Aurelia, who was naturally despondent over the death of her daughter. There was speculation at the time of her death that Sylvia had suffered from emotional and perhaps even mental problems for most of her life, a subject which Aurelia avoided.