MONDAY The perniciousness of apartheid, as well as its utter inanity, is well distilled in the person of Sandra Laing. While born to white parents, her darker complexion caused authorities to classify her as black at age nine, then white again at age eleven. For people too casually comfortable with discrimination, Judith Stone’s account of Laing’s life, When She Was White: The True Story of a Family Divided by Race [in South Africa], is a…