From the beginning of her career in writing for young audiences, Matas has infused her works with a prominent social voice, a trait that has persisted into her young adult novels. In a discussion with Jenkinson, Matas elaborated on how this social dimension became integral to her writing. She was brought up in a highly political household. Her father was elected to the local school board, eventually becoming its chairman, and he pursued other public offices before being appointed as a judge. As a result, political discussions, current world events, activism, and ways to enhance the human condition were common topics at the dinner table. With such a deep-rooted interest in social issues, Matas noted that it was only natural for these themes to emerge in her writing.

Specifically, Matas's social voice is prominently expressed in her novels about World War II. During a conversation with Nodelman, Matas pointed out that the era surrounding World War II provided her with a rich tapestry of dramatic narratives. It allowed her to delve into complex issues and place her characters in life-or-death scenarios where they faced moral challenges. In that same interview, Matas admitted her deep interest in the Holocaust, stating that its compelling fascination for her lies in its evil. For Matas, studying the Holocaust is an exploration of the darkest aspects of human nature. Daniel's Story offers a personal perspective on this twentieth-century catastrophe, contrasting with the impersonal statistics used to count the dead. By employing a chronological narrative, Matas illustrates how unchecked evil expanded in both scope and depravity. As Daniel noted:

"Yes, I can see from going through these pictures how it all started slowly and then got worse and worse and how the German people didn't try to stop it and how slowly all our rights were taken away until we were nothing but bodies being shipped out."

Matas also highlights moments where, if someone had spoken up or taken action, history might have been altered. For instance, while the family was still in Frankfurt, Daniel observed, "The Germans would have gladly let us go, but no country would open their doors to us. They got together at a conference and decided that they didn't want us any more than Germany did. Yes, they took a few—just not too many."

In her autobiographical piece in Something about the Author, Matas highlighted a pivotal scene in Daniel's Story. This scene unfolds when Daniel's sister, Erika, shares her belief with Daniel and his girlfriend, Rosa, that the world consists of individuals, each capable of both good and evil, and that everyone must accept this truth. Erika poses the question, "What are our choices?" and then answers it by outlining what she considers the three possibilities: "We can despair and curse, and change nothing. We can choose evil like our enemies have done and create a world based on hate. Or we can try to make things better." In their darkest moments, Daniel and Rosa both lean towards despair. Daniel, while at Auschwitz, witnesses bodies being incinerated in open pits because the crematoria can't keep up. It is during this time that Daniel contemplates taking his own life. "And I almost threw myself in with them. That was the closest I'd come to ending it all. . . . Perhaps it would be better to resign from the human race altogether." Rosa also experiences moments of hopelessness, such as when she says, "All this struggle . . . and for what? I still believe they'll try to kill us all before the war is over." After Buchenwald is liberated, Daniel...