Caxton is an important secondary character who functions as a mentor and paternal surrogate to Lilian. While her relationship to her biological father is often strained, Caxton provides love, guidance, and wisdom. He respects Lilian’s talents and ambitions, but he is also not shy to rebuke her when he thinks she is going down the wrong path. He both loves and admires Lilian, and he is able to love her unconditionally even when he observes her shortcomings. The model of love that he extends contrasts with Lilian’s more strained relationship with her biological father, and the oppressive patriarchal control that Isabel’s father exerts.

Caxton is initially presented as a lonely and isolated figure, but it is revealed late in the novel that he enjoys a loving relationship with a male partner. While Caxton’s relationship must be kept secret due to the social stigma and legal consequences surrounding same-sex relationships in early 20th century England, his wisdom and emotional maturity are grounded in a loving and supportive partnership.

Caxton’s care and regard for Lilian are affirmed when he pays off her father’s debts, frames it as “an investment,” and offers her partnership rather than apprenticeship: “I kept you apprentice too long. I was afraid you would leave, you see, and you did anyway so more fool me” (372). The bindery she inherits is not a gift; it is the fruit of a relationship that was always more than employment.

Harry is Lilian’s primary love interest. He is a local Oxford boy who works at a tavern at the start of the novel and eventually takes a new job at the university press to be closer to Lilian’s world. Harry and Lilian’s relationship can be classified as a “second chance romance”: prior to the start of the novel’s plot, they were engaged but the relationship ended when Lilian found out she was pregnant and chose to terminate the pregnancy. Harry had wanted a family, and “his heart was broken” (252).

As Lilian becomes more enmeshed in the mystery, Harry shows his steadfast loyalty and support, even when he doesn’t fully understand what is happening. Harry is sometimes critical of Lilian’s erratic and mysterious behavior, especially when she seems to be endangering herself. However, he shows his willingness to be a true partner: He doesn’t question her need to pursue her goals and instead seeks ways to support her. Harry also shows self-awareness and an ability to reassess his past actions. He tells Lilian that “I didn’t listen to you when we were younger. You said you didn’t want the family, the mother’s life, but I tried to force it on you and then I hated you for taking control of yourself” (388).

At the novel’s conclusion, Lilian reveals the whole story of recent events to Harry, including her tryst with Charlie. Harry decides to accept her and affirms his willingness to marry her and build a new life together. Harry’s personal growth makes him the right partner for Lilian. He is no longer threatened by her intelligence, drive, and ambition. By showing her the mysterious book he has found, Harry demonstrates his willingness embrace all aspects of Lilian and love her unconditionally.

Charlie is a secondary character who represents an additional love interest for Lilian, participating in a love triangle with her and Harry (although the two men never meet). Charlie works in Grieves’s London bookshop and crosses path with Lilian as she begins to investigate the mystery. He readily assists Lilian, providing important clues and access to Bell books. After Devlin attacks Lilian, she is shaken and lonely, and Charlie offers easy comfort with no history and no expectations: “Suppose I like you. Simple as that. I know I’m not much, don’t have anything to offer you, but I’m not all bad” (143). Charlie functions as a foil to Harry: He is emotionally uncomplicated, eager to support Lilian without questioning her, and doesn’t demand anything of her. However, he lacks the history and emotional intimacy that her bond with Harry offers. Lilian eventually tells him, “I’m sorry I can’t give you what you deserve” (268), foreclosing the possibility of a deeper relationship because she is preoccupied with both the mystery and her reemerging relationship with Harry.

Isabel Chatton is a secondary protagonist and the central character in the “plot within a plot” (the events in the 1851-52 timeline, which Lilian gradually uncovers). As a young woman from a few generations earlier, Isabel functions as a foil to Lilian, revealing both the progress women have made in half a century, and how many of their struggles remain consistent. Isabel is the daughter of a wealthy man; she has the privileges of high social and economic status, but also the pressures.

Isabel’s defining characteristics are her intelligence, stubbornness, and insistence on her right to choose her own destiny. Isabel falls in love almost at first sight with William Heathfield, and their relationship shows that she values intelligence and mutual respect. Isabel refuses to renounce this relationship despite her father and uncle’s cruelty and violence. Not only does she remain stubbornly faithful to William (and thus, to her own heart), but she martials the resources she has access to. Isabel begins meticulously documenting her experiences and the context into which her son is born, hoping to protect both her baby and herself. As a woman who lacks legal rights and cannot physically overpower her captors, Isabel relies on her intelligence. She defiantly tells her father that “When you die, when all you have made comes to me, I will dance on your grave” (149).

Isabel’s judgement can sometimes be shaped by her intense love for William; she readily forgives him for murdering her cousin, Julian, and even assists with hiding the murder weapon. Decades later, when Lilian questions her about these events, Isabel is unrepentant. The force of Isabel’s love also leaves her unable to move forward after William’s death; 50 years later, even though she knows that he is never coming, she lives as a recluse in the remote location where she vowed to wait for him. Isabel signals some character development when she expresses her interest in reaching out to her son: the news that he is alive gives her the motivation to explore a new future, rather than remaining trapped in the past.

William is Isabel’s love interest; he becomes her husband in secret and is the father of her child. William comes from a modest but respectable family and meets Isabel by chance at a London theatre. William is curious and intellectual; he loves word puzzles such as acrostics and reading novels by authors such as Abel Bell. William’s love for Isabel makes him bold: He is the one to propose that “we could elope. Once married, they cannot deny us” (231). Although he is often shut out of the events unfolding in Isabel’s life, he does everything he can to remain in contact with her.

The intensity of William’s love sometimes makes him reckless. He corresponds with Isabel although it is extremely risky to do so, lingers near her house, and makes it possible for Silas’s men to follow him (which eventually leads to his murder). He also kills Isabel’s cousin, Julian, in a duel after learning that the two of them have become engaged. William has a limited role in the novel and readers never have direct access to his thoughts and feelings, but the force of Isabel’s enduring love implies that he was charismatic. William dies young but his final words reveal his loving and loyal heart: he speaks either Isabel’s name, or “Bell” (the name of the author), alluding to their secret history.

Julia is eventually revealed as the antagonist. She appears briefly and seemingly benignly when Lilian finds the first Bell book. It is only much later that Lilian deduces that Julia is the one who has been seeking the set of Bell novels and the documents contained within (Julia pays Devlin to carry out violence on her behalf). Julia is the daughter of Silas Chatton, and Isabel’s first cousin (although she was born decades later). Julia learned about her father’s obsession with finding and eradicating Isabel’s hidden documents. Once she had her own son, Julia became increasingly determined to eradicate the claim of Isabel’s son. She tells Lilian that “a parent does whatever they must for their children” (360), revealing her primary motivation. She has inherited her father Silas’s appetite for violence and dressed it as maternal duty.

Julia reveals her cruel and violent nature when she confronts Lilian and physically fights with her for control of the documents. Julia succeeds in burning and destroying Isabel’s testimony, but her determination costs her her life. Julia is immolated in the fire she triggers herself, symbolizing how her obsessive tendencies eventually destroy her. She does not display any development or growth and remains imprisoned by her fixation on family lineage and inheritance.