You might want to analyse the theme of bravery in this excellent children's book. During the course of the novel, Annemarie is shown to grow in her understanding of the concept of bravery and what true bravery actually looks like in the very real and horrendous situation that the Jews in Europe are facing. Consider the following quotation, which is said by Uncle Henrikk to Annemarie:
It is much easier to be brave if you do not know everything. And so your mama does not know everything. Neither do I. We know only what we need to know.
Uncle Henrik explains to Annemarie why Mrs. Johansen concealed the truth about Annemarie's Great-aunt Birte. This quote is significant because Annemarie realises that complete knowledge--something she feels she ought to possess--is not actually always a good thing. Annemarie equates being told the complete truth with being an adult, and so when she discovers that she has been lied to, she is annoyed because she feels that she is being treated like a child. In this quote, Henrik explores how too much knowledge could actually be a bad thing and might even make it harder to be brave. Of course, this is something that Annemarie will discover that very night.
However, this quote also is important because of the way in which it helps Annemarie to come to a deeper and more accurate understanding of bravery. Bravery, to Annemarie, is the most important characteristic one can possess. However, Annemarie by the end of the novel comes to realise that bravery is not equated with facing every danger or threat immediately.