Throughout the novel, hearts serve as a motif, consistently reinforcing the theme of The Complexity of Love. Giovanni’s original heart, which is “made of metal and wood and shaped not like the organ but like a symbol of a heart” (23), contains a single drop of Victor’s blood and grants him the capacity to love. The rest of the artificial hearts in the story are constructed by the protagonist. For Victor, the hearts are a true labor of love. The first one he builds takes him six years to complete, and even then it seems “crude and sophomoric and indescribably human” compared to his father’s masterpiece (31). Victor gives this heart to Hap although he originally intended it for Giovanni. This change in plans emphasizes the novel’s assertion that love comes in many forms: The first sort of love Victor experiences is familial love for his father, and he is later able to establish other types of connections, including romantic love. Hap’s heart gives him a new life and supports his transformation from a killing machine to a person capable of immense love.

When Giovanni learns that Hap has a heart, he offers his fellow android some words of wisdom: “It’s strong, but fragile.