The book's brilliance—and its challenging nature—come from two key artistic decisions by S hriver. First, the novel exploits and forces us to acknowledge our greedy desire to see horrible things happen, as long as they don't happen to us. We know (or think we know) from the opening pages of the novel, that Kevin is a mass murderer. What makes the novel such propulsive reading is an impatience to get there, to actually see Kevin do the Bad Thing that we've been promised, against which all of his other ugly little misdeeds—from ruining his mother's newly wall-papered office, to cruelly mocking a girl at a school dance, and yes, to potentially causing his little sister to lose an eye—pale in comparison. Watching those murders happen seems for most of the book like it will merely be a dirty, vicarious thrill: after all, Eva is safe, she's writing to her estranged husband, who seems to have gotten custody of their daughter in the split.
The moment also dramatically rearranges our understanding of Eva. At the beginning of the novel, she is both personally and morally sympathetic, a bohemian travel guide writer deeply in love with her husband, and the person who sees her son for the sociopath that he is, the person who, if the warnings were heeded, would have saved lives, saved her daughter's eye. Perhaps she could have been a warmer mother to him—Shriver is unstinting in describing Eva's revulsion against a son who refused to breastfed, refused toilet training until he was six, who masturbates in semi-public simply to disturb her. Eva cannot conceal her hatred and fear of her son, even breaking six-year-old Kevin's arm in a fit of parental rage.
Eva is not an easy character to judge, and that's an appropriate difficulty in the kind of situation where we would be more comforted by easy explanations. It's easy to sympathize with and understand the agonized grief of parents who lose their children to cruel chance. But it's impossible to imagine the deranging grief and guilt that the parents of the killers must experience, though the statement from Seung-Hui Cho's family in the wake of his murders at Virginia Tech offers a hint of that vast ocean. Shriver, in the marvelous and terrible piece of clockwork that is her novel, has given us a character who is not guilty nor innocent of her son's atrocities, and forces us to linger in that uncomfortable ambiguity.