The book "**Once**" by **Morris Gleitzman** explores several significant themes and topics that can help you draw connections to other books in a library. These include:
* **War** The backdrop of the story involves the horrors of war experienced by Felix. 【1】
* **Family** The theme of family is central to the narrative. 【1】
* **Friendship/Relationships** The book explores the importance of friendship and relationships. 【1】
* **Hope** Despite the grim setting, the theme of hope is prevalent. 【1】【2】
* **Hiding** The characters in the story are often in hiding. 【1】
* **Storytelling** The power and importance of storytelling is a key theme. 【3】【4】
* **Innocence and Ignorance** The story also deals with themes of innocence and ignorance. 【3】
* **Antisemitism vs. Human Dignity** The book explores the conflict between antisemitism and the value of human dignity. 【3】
* **Morality, Violence, and Complicity** The story touches on morality, violence, and complicity. 【3】
* **Resilience** The theme of resilience is present in the novel. 【2】
* **Imagination** The book also explores the theme of imagination. 【2】