Sylvia is a story of revenge but the underlying theme is the invisibility of older women. At certain ages and stages women are far more likely to be invisible than men of the same age. This novel deals with one woman's reactions to this sudden feeling of invisibility and describes how she uses this phenomenon to avenge the deaths of her son and then her husband. Because she comes from a small country town, where she was never aware of feeling invisible, the city way of creating anonimity does not register as a safe way of dealing with so many people. It rather makes her believe that no one cares. The fact that she finds it difficult to make friends in this environment does not help matters. When she discovers the people she feels were responsible for her son's death - and subsequently her husband's death - she gradually realises that she can wreak revenge on them without being even suspected, let alone caught.