Grief
As implied by its title, grief is the book's central theme. Zauner suffers the loss of her mother shortly after finishing college. This loss makes her feel that she missed opportunities to spend time with her mother. She wishes they hadn't fought so much when she was in high school. She is devastated that she is unable to go to Korea with her and experience all of the places her mother had planned to take her to. In the first chapter, she refers to the fact that she cries in the aisles of H Mart because she has no one to call and ask if she has purchased the right ingredients for a dish. What she means is that her experience of grief is intertwined with moments that remind her of the magnitude of her mother's absence. Grief, for Zauner, is the continual reemergence of this pain.
Food
Directly connected with grief, food is another main theme of the book. Zauner's earliest memories of her mother are related to food, as are many of her memories of her mother's final days. Food acts as a kind of grounding for Zauner throughout the book, giving her a sense of her cultural roots as well as a reference point for many of her recollections of childhood. Later in the book, as she deals with her mother's death, she comes to find solace in learning how to cook traditional Korean dishes, as it provides her with a way of holding onto her mother's memory.
Motherhood
Motherhood is another important theme in the book, as Zauner talks about the intensity of the bond she shared with her mother. Her mother would often instruct her to "save her tears" for when she died, suggesting that that was the most intense emotional pain she would ever feel. When Zauner's grandmother dies, her mother is completely bereft. Likewise, in the moment in which her mother dies, Zauner is in total despair. At one point, when it is clear her mother will die, Zauner and her mother watch an interview with actress Mariska Hargitay in which she tears up while talking about the loss of her mother. In turn, Zauner and her mother begin to cry, as Hargitary still struggles to talk about this loss so many years later.
While Zauner had a complex relationship with her mother, she recognizes that it was one of the most essential of her life and had a seismic impact on everything from what she ate to how she saw herself. Without generalizing, the book highlights the intensity of their mother-daughter bond and suggests the commonality of this experience.
Language
Language is another major theme in the book. Zauner speaks basic Korean but is not fluent. As a result, she often finds herself straddling a cultural divide as she struggles to communicate with her relatives. She faces this difficulty most acutely when she visits her mother's sister, Nami, after her mother's death. She is worried about not being able to communicate and at the end of the trip struggles to find the right way to tell her how much the trip meant. At the same time, she still manages to get the point across in the end, implying that there is a way to communicate meaningfully across language barriers.
Homecoming
Another major theme in the book is the idea of homecoming. Zauner returns home to Eugene Oregon to care for her mother when she becomes ill with cancer. Likewise, she travels back to Korea a number of times as both a child and an adult. At the end of the book, she finishes her band's tour in Seoul and has an emotional reunion with her relatives. This idea is a complex one for Zauner as she feels strong ties to both places despite living in Philadelphia and, later, New York. While one is the place she grew up, the other gives her a more overt connection to her mother, as her relatives still live there and she is able to see her mother's favorite places and eat her favorite foods. In both cases, going home means reckoning with what has changed (the loss of loved ones, the changes in a city) while maintaining some connection to the past.
Music
As might be expected from Zauner's career, music is also a major theme in the novel. In the early part of the book she details her blossoming love for it, talking about early open mic performances and concerts. Later, she also discusses playing in the punk rock group Little Big League and going on tour. Finally, at the end of the book she describes the unexpected success of her current band, Japanese Breakfast. While she describes the financial difficulties of this lifestyle, as well as the frustrations of being on the road so much, the portrayal of her music career is ultimately a loving one. Music serves as an emotional outlet for Zauner, as she writes Psychopomp, Japanese Breakfast's first album, about losing her mother and puts her mother's image on the cover. In this way, she is able to take her memories of her mother, and the pain that accompanies them, and transform it all into something moving—not unlike the book itself.
Cultural Identity
Cultural identity is also an important theme in the book. Zauner is biracial, having a Korean mother and white father. As a child at school, she is perceived as not being white and sometimes treated unkindly for it. Similarly, when she is in the presence of other Korean people she feels that certain things (not speaking fluent Korean, not being able to cook certain dishes) mark her as somehow inauthentic. As she navigates these two parts of her cultural background, she often ends up feeling as though she is not quite either thing. Still, at the end of the book, she is able to feel a deep connection to her Korean heritage as she feels that her band's concert in Seoul provides her with some measure of closure.