The unnamed narrator is an aspiring writer and former fact-checker living in Brooklyn, New York. She is intensely introspective, constantly observing her surroundings and relying on fragments of science, philosophy, and myth to make sense of her world. Striving to reconcile her desire for artistic freedom with the everyday demands of domestic life, she frequently questions her choices and her evolving identity.

Introduced as a fellow creator who makes city soundscapes and works late nights at a radio station, he quickly forms a deep bond with the Narrator. He is steadfast and deeply grounded, standing in contrast to the Narrator's anxious energy. As their relationship progresses into marriage and parenthood, he represents both a source of love and an unwitting tether to a conventional life that challenges his wife's artistic ambitions.

A close friend of the Narrator, the Philosopher is an intellectual companion who offers her a peaceful refuge from her chaotic thoughts. He works as a lecturer and shares a workplace with the Husband. He serves as a vital sounding board for the Narrator, helping her process her complicated feelings about art, existence, and relationships without judgment.

The Narrator's sister is a practical and supportive presence who has left urban life for a quieter existence in Pennsylvania. Sharing a complex childhood with the Narrator, she understands her sibling's anxieties on a fundamental level. She acts as a grounded advisor, frequently offering an alternative perspective on metropolitan struggles and domestic concerns.

A young woman whose sudden relevance in the Husband's life brings a sharp, painful clarity to the Narrator's marital anxieties. She is described simply as being "easier" than the Narrator. Her entry into the couple's orbit acts as a severe catalyst for the Narrator's existential and emotional crises.

The young child of the Narrator and Husband. As an infant, she is difficult to soothe, which deeply exhausts the Narrator and exacerbates feelings of isolation. As she grows, she develops a distinct and curious personality. She is deeply loved by her parents even as her care demands massive sacrifices of the Narrator's personal time and artistic ambitions.

A former space program participant who hires the Narrator to ghostwrite his book about the cosmos. His project provides the Narrator with much-needed income. His obsession with specific historical details, such as the Golden Record, feeds the Narrator's own fixations on isolation, connection, and survival.

A university student in the Narrator's writing class. Lia struggles with severe depression and feelings of meaninglessness, culminating in a crisis that prompts the Narrator to visit her at the hospital. She serves as a dark mirror to the Narrator's own internal despairs and search for purpose.

A former romantic partner of the Narrator who briefly re-enters her life. Although they do not resume their romance, his presence triggers memories of the Narrator's past, reminding her of who she was before the heavy responsibilities of marriage and motherhood took over.

A friend of the couple who visits them during the exhausting early days of parenthood. Bothered by the relentless crying of the colicky baby and the soothing CD playing in the background, R quickly leaves. This early departure illustrates the social isolation new parents face when their lifestyle changes.