The themes of death and suicide, as well as the grief that inevitably follows both, are ubiquitous throughout the novel. The narrator repeatedly refers to a number of famous figures who have committed suicide, most often writers and philosophers. She even considers deaths that are not necessarily suicides but which seem instead to be acts of resignation—such as Houdini, whose final words were “I am tired of fighting, I do not want to fight anymore.”

The thought process of a suicidal person is explored in great depth, and special care is taken in debunking the common myth of the “suicide note.” It is said that people who take the time to “scribble a goodbye” usually lose their nerve. Indeed, “you” left no note whatsoever, something that is incredibly difficult for the people around him to accept, particularly Wife Three.

In the end, the narrator finds a conclusion in the form of the testimony of another. Mourners feel as though they owe it to the dead to search for the truth, but the reality is that those who end their own lives without leaving letters desire silence and mystery—and it may ultimately be best to honor and preserve this mystery.

The morality of suicide is explored in great detail, and the question of whether or not it is an acceptable option is one that weighs heavily on the narrator’s mind. She listens to a radio program that condemns all suicide as cowardly, selfish, and evil. However, she cannot bring herself to resent “you” in this way. She understands that, much like Houdini on his deathbed, “you” was simply tired of fighting, and his act didn’t necessarily have to be about anyone else.

In the novel, the relationships between humans and domesticated animals are explored thoroughly—and often humorously, creating a juxtaposition with the grief surrounding the other themes of the work. The British writer J. R. Ackerley is repeatedly referenced, primarily in the context of his controversial memoir My Dog Tulip, which is so intimate a portrayal of Ackerley’s canine friend that it details the dog’s bowel movements and “heats.” Ackerley is portrayed as one extreme, given his belief that a dog and a human should be equal friends and that the dog should have complete sovereignty over its own life.

Indeed, the amount of control that the narrator has over Apollo is a source of constant contemplation. She considers that in a scenario involving a full-on conflict between herself and Apollo, he would, as a Great Dane, be the obvious victor. In fact, this is a somewhat tangible threat before she and Apollo bond. The degree to which dogs depend upon humans—and the degree to which they experience complex human feelings, such as grief, betrayal, and understanding of death—are explored in detail.

As Apollo grows old, as do all living things, the narrator is forced to contemplate the demise of pets and how it relates to their owners. She recalls a memory in which she took one of her dying cats to be “put to sleep” but, due to a botched or otherwise ineffective sedating process, was unable to be with the cat when she died. The question of whether animals see euthanasia as a relief or as a betrayal weighs heavily upon the narrator. She is consumed by an anxiety revolving around the assumption that a pet sees the human as a god: when it realizes that it is dying, she worries that it is confused and hurt by the perception that the human either can’t or won’t do anything about it.