Jessie is a 40-year-old librarian from the New York Public Library who travels to France on a salary to join the American Committee for Devastated France. Nicknamed "Kit" by her fellow volunteers, she is shy, highly imaginative, and struggles with self-doubt instilled by her overbearing boss back home. She holds a deep conviction that children in war zones need literature and safe spaces to maintain their hope and imagination.

Wendy is a young, aspiring writer working in the Remembrance department of the NYPL. She guards herself socially due to past personal trauma and struggles to connect with her classmates in her writing program. Her life begins to change when she discovers an archive of the American Committee for Devastated France and feels a deep kinship with the forgotten women who served there.

Marcelle is a 15-year-old French girl living in a destroyed quarry with her family after their home was bombed. She is rebellious, quick-witted, and hungry for a life beyond the ruins of her village. She quickly idolizes the independent American women of CARD, eager to read their books and learn how to drive their supply cars.

Anne Morgan is the wealthy, fiercely intelligent founder of CARD. She uses her high-society connections and vast resources to bring attention to the suffering in France and fund the rebuilding efforts. She is generous but commanding, accustomed to organizing large-scale relief and demanding hard work from her volunteers.

A physician and the president of CARD, affectionately known as Dr. M.D. by the volunteers. She is strict, pensive, and highly focused on the organization's logistics, budgets, and volunteer discipline. She acts as a pragmatic counterbalance to Anne Morgan's generous impulses.

Winnifred is Kit's overbearing boss at the NYPL and a pioneer of the children's reading program. She is highly critical, firmly believes her methods are the only correct way to manage a library, and actively discourages Kit's departure for France. Her judgmental voice frequently occupies a space in Kit's anxious thoughts.

Professor Hill is Wendy's writing instructor. Cynical, bitter, and highly critical of his students' work, he regularly disparages their stories as trite or shallow. He uses his classroom to project his own disillusionment with the publishing industry onto his aspiring writers.

Tom is an American soldier and mechanic stationed near the French front lines. He is respectful, observant, and shares Kit's deep appreciation for literature. He provides Kit with a romantic connection that allows her to break away from the restrictive social expectations of her hometown.

Roberto is a knowledgeable librarian at the NYPL who helps Wendy with her archival research. He was barred from working directly with the public by the library director, a demotion that fuels workplace rumors. He is patient, encouraging, and uses his access to historical boxes to foster Wendy's historical curiosity.

Kate Lewis is a fearless volunteer driver for CARD, affectionately known as the "Wild Card." She rejected the life of an idle heiress to serve in France following the death of her father. She is practical, unafraid of manual labor, and acts as a supportive friend to the other women in the organization.

Known to the volunteers as "Breckie" or the "Calling Card," Mary is a widowed nurse who checks on village families and tends to their medical needs. She draws on her own profound personal losses to empathize with the grieving French women, finding healing and purpose through her service to others.

Marie, nicknamed "Cookie" or the "Recipe Card," is the designated cook for the organization. Unlike many of the wealthy heiresses volunteering for CARD, she comes from a working-class background. She initially keeps to the kitchen out of an ingrained sense of class division, feeling she does not belong at the main dining table.

Sidonie is a grieving, reclusive villager who lost her husband and baby early in the war. She initially resents the American volunteers, viewing them as wealthy tourists who cannot understand her pain. Slowly, through the introduction of literature and the empathy of the CARD members, she begins to rejoin the community.

Madame Moreau is Marcelle's strict and pragmatic mother. Living in a quarry with her children after their home was bombed, she tries to protect them by discouraging unrealistic hopes and dreams. She views the American women with suspicion, fearing their influence will make her daughter unfit for a traditional French marriage.

Madame Petit is a fiercely protective French mother who was separated from her twin daughters at the start of the war. With one daughter returned injured and the other missing, she remains stubbornly attached to her home and remaining possessions, terrified of losing anything else to the conflict.

Jeanne is Madame Petit's surviving twin daughter. She returned from German captivity missing a foot and refuses to discuss what happened to her. Despite her trauma and physical limitations, she maintains a quiet hope for the future and enjoys the books Kit brings to the village.

Henri is a young French soldier who lost an arm in the war. He falls quickly in love with Jeanne Petit after spotting her in the village. He uses Kit's library to facilitate his courtship, asking Kit to deliver poetry collections with notes hidden inside.

Meredith is a student in Wendy's 1987 writing class. After facing harsh criticism from their professor, she shares her creative struggles and visual storyboarding methods with Wendy, leading to a mutually supportive friendship that helps Wendy break out of her isolation.

Eugene Morel is a progressive French librarian who advocates for the implementation of the Dewey Decimal system in France. He supports Kit's innovative ideas for accessible community libraries and praises her willingness to stand up to traditionalist library directors.

Vincent Charon is the traditionalist director of a prestigious library in Paris. He looks down on community libraries, believes different social classes require separate reading materials, and dismissively suggests that a woman librarian is only good for dusting bookshelves.