Dita is a fourteen-year-old Jewish prisoner in the Auschwitz-Birkenau family camp who acts as the librarian for a secret school. Having lost a comfortable life in Prague, she holds onto her sanity through a profound love for literature. She maintains a strong moral compass and questions the terrifying world around her, finding solace in the eight smuggled books she fiercely protects.

Fredy is a German Jew, passionate Zionist, and athletic instructor heading the school in the Family Camp. He commands immense respect and instills pride in his young students, dedicating his energy to shielding the children from the horrors of the camp. Beneath his disciplined exterior, he carries the heavy burden of leadership and harbors dangerous personal secrets.

Mengele is a high-ranking SS doctor known for his chilling indifference and brutal medical practices. He often whistles classical music as he wanders the camp, creating a terrifying contrast between beautiful melodies and his horrific actions. He embodies the absolute cruelty and clinical detachment of the Nazi regime.

Miriam is a wise, compassionate woman who helps guide the children in Block 31. Separated from her influential husband, she provides a steady, comforting presence for the young prisoners. She frequently acts as a philosophical mentor to Dita, encouraging the young librarian to look beyond her immediate anger.

Volkenrath is a sadistic women's supervisor at the Bergen-Belsen work camp. Rumored to be a former hairdresser, she abuses her authority to terrify and demean the sick and starving prisoners under her watch.

Viktor is an SS officer whose exposure to the camp's brutality slowly fractures his belief in the Nazi cause. His shifting conscience accelerates when he develops a forbidden attraction to a Jewish girl across the fence. This affection drives him to consider massive personal risks to protect her, standing as an anomaly among his fellow guards.

Liesl is Dita’s mother, a woman who tries to maintain a pleasant demeanor and comply with the rules in the face of escalating horrors. She uses a mask of neutrality to cope with the trauma, though she harbors a quiet, fierce strength that surfaces when her daughter's survival is on the line.

Formerly a successful professional in Prague, Dita's father has been stripped of his livelihood and health by the Nazi regime. Inside the camp, he tries to maintain normalcy and dignity by teaching his daughter geography, math, and Latin, despite his failing physical condition.

Margit is Dita’s best friend, a fellow teenager navigating the horrors of Auschwitz. The two girls bond over shared secrets and memories of their pasts, providing each other with vital emotional support and a brief escape into normal teenage conversation.

Rudi is a nineteen-year-old Jewish prisoner who secures a position as a registrar, granting him civilian clothes and mobility around the camp. He secretly works with the resistance movement and falls deeply in love with a girl on the other side of the camp fence, risking his safety to communicate with her.

Alice is a beautiful Jewish prisoner from the September transport who catches Rudi's eye. She bravely exchanges small items and conversation with him through the deadly chain links, finding brief moments of joy and affection in an otherwise bleak existence.

Ota is a highly educated, serious teacher in the camp who speaks English and possesses deep literary knowledge. A former communist from a wealthy family, his sharp intelligence and storytelling abilities make a strong, lasting impression on Dita.

Professor Morgenstern is an elderly teacher in Block 31 who often appears confused or absentminded to the younger prisoners. He spends time folding origami birds and engaging in seemingly irrational behavior, which masks a deeper awareness of camp survival tactics.

Renee is a friend of Dita and Margit who becomes the uncomfortable focus of an SS guard's attention. She struggles with the harsh judgment of her fellow prisoners as she handles this dangerous, uninvited affection, eventually seeing the guard's unexpected humanity.

Yakub is Miriam's husband and a former Jewish Council leader. Because of his high-profile position, he was separated from his family and sent to Auschwitz I, a notoriously brutal political prisoner's camp.

David, sometimes called Schlomo, is a resistance member forced to work in the special operations unit that prepares prisoners for the gas chambers. He passes vital, traumatizing intelligence to his fellow resistance fighters, carrying the heavy guilt of his forced labor.

Ludwig is a German Kapo in the camp who shares a dangerous, hidden connection with Fredy Hirsch. Their relationship highlights the complex and perilous dynamics of finding comfort within the strict, lethal hierarchy of Auschwitz.

Siegfried is a male prisoner who becomes involved in a high-stakes plan orchestrated by Viktor Pestek. He must rely on disguise and immense nerve to navigate the dangerous territory of the camp's exit.