The family book, meticulously maintained over generations, includes a record of births, marriages, deaths, and other significant events in the Buddenbrooks’ family life, representing a physical manifestation of the family’s heritage and societal status. The act of recording in the family book is marked by solemnity and reverence. Over the course of the novel, the family book comes to represent a record of The Decline of the Buddenbrooks with the addition of events that signal a break from the Buddenbrooks’ definition of success and social standing such as when Tony enters the events of her divorces. When little Hanno playfully adds two lines to the end of his father’s writing, it signifies to Thomas the end of the family line. Thus, as the novel progresses, the family book evolves in its symbolic significance, mirroring the family’s gradual decline.

The sea’s presence in the novel provides a backdrop to the Buddenbrook family’s story, set in the coastal town of Lübeck. The sea also represents the essence of change, the unknown, and the forces beyond human control.

The sea appears at key moments in the novel, when the characters travel to the holiday resort of Travemünde. Depending on the circumstances, the sea represents freedom, a sense of escape, or downfall.