LitCharts assigns a color and icon to each theme in The Book Thief, which you can use to track the themes throughout the work.
Death
Words and Language
Books
Stealing and Giving
Color, Beauty, and Ugliness
Summary
Analysis
One of Rosa's customers can't afford to employ her anymore because of war rationing, which infuriates Rosa. She decides to make Liesel deliver the washing from now on, as she is more pitiable-looking and harder to fire. Rosa instructs her (with much saumensch-ing) on the strict rules of the pick-up and delivery. Liesel comes to enjoy the work, and starts to notice the quirks of the customers. Most noticeable is Frau Hermann, the mayor's wife, who lives in a cold house and never says a word.
The seemingly distant war begins to encroach on the peaceful life of Himmel Street, beginning with economic cutbacks like this. The Hubermanns are already poor, so Rosa losing customers is a bad sign of things to come. Frau Hermann returns as a mysterious, silent figure – she is being built up to become more important later.
Active
Themes
One day at school the children are supposed to write letters to each other, which gives Liesel the idea to write to her mother. Hans is visibly uncomfortable when she asks him about it, but Liesel chooses to ignore her own apprehensive feelings and sends a letter anyway. That night Liesel overhears Rosa and Hans discussing her mother, and how she has probably been taken away.
More situational irony as Liesel doesn't know (or doesn't want to know) what has happened to her mother, but the reader (and the Hubermanns, and Death) can imply from historical facts that she has been arrested or killed by the Nazis. Again Liesel chooses to repress her feelings.