What is the theme in Behind the Scenes at the Museum by Kate Atkinson?

The main theme in the novel, Behind the Scenes at the Museum, is death. Over the course of the novel, the main character, deals with a number of death, specifically deaths of people in her family. Some of these deaths are extremely traumatic. Ruby's father, for example, dies of a heart attack when she walks in an finds in the arms of a woman..... a woman who is not her mother.