The Inscrutability of Women
The two men at the center of this story are misogynists of the worst kind: the kind that hate women because they fear them and fear them because they never get to know them. The uncle never even tries to get to know women until he meets Rachel. By itself, that might suggest he was right all along, but that perspective only applies if one believes his story rather than the story that he was suffering from a brain tumor. The nephew’s misogyny is created by the uncle by raising him with any significant contact with females. Can anyone be surprised that these two men might well fall under the spell of a black widow or that they might well create a black widow Frankenstein-like out of their own paranoid insecurities? The larger thematic suggestion, obviously, being that most men are at the same very risk to one level of another because they find women inscrutable and then would rather just eliminate the problem than address it.
Incest
The title immediately suggests that the story is about incest, but it is not really sexual incest that is being explored. Rachel is, after all, the distant cousin of both the narrator and his uncle, but Ambrose and Philip are closely related by blood. So when Philip marries his uncle’s widow, the incestuous undertones at play seem really more about the two men to each other than each man to the woman. In addition, even though Rachel is the wife, it is the nephew who winds up inheriting the estate, suggesting a closer bond there than anything even remotely considered normal. Also adding to the theme of incest is the passage of the bad blood of misogyny from uncle to nephew.
The Unknown
The power of that which is unknown over the human psyche is the thread which ties every other aspect of the novel together. Philip has been raised in such a way that he literally knows nothing about women. His uncle has willingly refused to try to learn about women, arriving at a conclusion uninformed by experience and being happy with it. Philip never knows for sure what the relationship is between Rachel and Rainaldi and is likewise never knows for sure whether his uncle was poisoned to death or whether his mind was poisoned by a tumor. The circumstances of Ambrose Ashley’s demise is the point at which the theme of the unknown transfers to the reader. Aside from the author herself and anyone she may have be personally discussed it with, no reader of the book knows for sure whether Rachel actually killed Ambrose or not, yet almost every reader likely has drawn a conclusion one way or the other. Therein lies the power of the unknown because reader has ever been right, yet most assuredly many have stood unmovable in their own conviction.
