The unnamed, gender-neutral narrator works as a professional translator in London. With a long history of passionate but chaotic love affairs, the narrator struggles between a desire for safe domesticity and an intense susceptibility to romantic obsession. Prone to deep reflections on language, biology, and the physical body, the narrator views romantic relationships as entirely consuming. The narrator maintains a contradictory moral compass, often pursuing married women while claiming to respect the institution of marriage.

Louise is an Australian-born woman with a doctorate in art history who spends her days restoring the antique Tudor house she shares with her husband. She feels trapped in an unhappy, passionless marriage. Desiring a deep, authentic connection, she persistently pursues the narrator for two years after first spotting them at the British Library. She is fiercely passionate and demands total commitment in romance.

Elgin is an eminent cancer research physician who abandoned his early altruistic dreams of practicing medicine in Third World countries for lucrative pharmaceutical research. Raised as an Orthodox Jew before breaking with tradition to marry a Gentile, he is primarily motivated by money, status, and professional prestige. His marriage to Louise is emotionally fractured, and he views her more as a prize that boosts his social standing than a true partner.

Gail is a hard-working, heavy-set older woman who manages a local wine bar in the north of England. She is plainspoken, perceptive, and deeply compassionate. Despite lacking conventional attractiveness, she offers steady companionship and practical wisdom. She serves as a grounding presence and a direct critic of poor decisions, refusing to let others wallow in self-pity.

Jacqueline is a young zoo worker who provides the narrator with a predictable, comfortable domestic life. Patient and domestic by nature, she represents the safety and routine of a conventional relationship, spending her evenings watching television. Beneath her quiet exterior lies a capacity for explosive retaliation when her stability is threatened or betrayed.

Sara is Elgin's deeply religious Orthodox Jewish mother. She survived a highly difficult labor to raise him, frequently reminding him that she was spared by divine intervention to serve him. Her eventual illness and death from bone cancer serves as the major catalyst for Elgin's career shift into oncology.

Esau is Elgin's highly religious Orthodox Jewish father. After squatting in a London house during World War II, he bought the property with gold. He maintains strict religious convictions and severs all contact with his son when Elgin chooses to marry outside their faith.

Inge is a radical Dutch anarcha-feminist and former lover of the narrator. She attempts to balance her fierce political convictions with a deeply romantic nature, leading to contradictory behavior like refusing to bomb the Eiffel Tower out of sympathy for the young lovers visiting the site.

Bathsheba is a former lover of the narrator. Their turbulent relationship ends with her passing on an emotional toll along with a substantial gift of guilt money, which funds the narrator's transition into a quieter life with Jacqueline.

Crazy Frank is a heavily built former boyfriend of the narrator who was adopted by midgets. Deeply devoted to his adoptive parents, he breaks the narrator's heart by cynically insisting that romantic love is merely a biological ruse.

Judith is a former lover of the narrator who worked at a botanical gardens. Highly particular in her romantic habits, she once locked the narrator out of a hothouse in the snow during a dispute and later burned the narrator's possessions.

Catherine is a former girlfriend of the narrator. Together, they shared a voyeuristic evening habit of peering into the living room windows of strangers to observe the inertia of typical domestic life.