Content Warning: This section of the guide describes depictions of antisemitic discrimination, violence, genocide in the context of World War II, and death by suicide, which feature in the source text.

Ten-year-old Felix Salinger is the protagonist and narrator of Then. In Once, the previous novel in the series, he ran away from a Catholic orphanage where his parents sent him to keep him safe from the Nazis. Felix is Jewish, and in Once, he was forced to come to terms with the horrific discrimination and persecution of Poland’s Jewish population during the Holocaust. Felix has a much more mature perspective on his situation in Then, for his outlook is born from the trauma he experienced in Once. He now knows that he is an orphan and fully comprehends the extent of the atrocities committed by the Nazis. He has also lost his surrogate family of Jewish orphans and the dentist, Barney, who kept them safe. Zelda is Felix’s only remaining family, and keeping her safe is the main problem that Felix faces throughout the novel.

Felix’s parents owned a bookstore, and so Felix grew up with a deep love of literature, particularly works by the British author Richmal Crompton.