What is a prominent theme in Milkweed? What are examples of it, and how do the examples reflect the theme?

Two of the most important themes in Milkweed are identity and innocence. Jerry Spinelli created a character who does not know his name at the beginning of the novel. He internalizes what others call out to him, “Stopthief,” and believes this is his name. By the end, he is living in another country and has been adopted. This unnamed boy is innocent in that he knows very little of the way society works. The action takes place during World War II, and as he learns more about various ways of life beyond his original homeless, nameless existence, he moves from innocence to knowledge. Sadly, much of that knowledge is hard to handle, including the prejudice and persecution that factored into the war. However, he also learns of compassion and generosity as some people help others to survive and escape the horrors around them.
In terms of identity, two possible relevant instances to discuss are his initial encounter with another boy, which leads to Uri’s giving him the name of Misha Pilsudski. Another instance is Misha’s going to live with Janina and her family in the ghetto. This incident could also be used for the theme of innocence. Misha witnesses the Jackboots’s persecution of the Jews and identifies with the Jews. He later learns that he is not a Jew. During this period, his identity is altered as Janina declares him part of the family, which he had not been previously. Although his identity does not change in regard to Jewishness, he formerly did not know about the importance of this category of personhood; not being a Jew becomes increasingly important as events unfold.
In addition to learning about the persecution of Jews, another phase of loss of innocence is through Misha’s witnessing the deaths of people around him. This knowledge is compounded by his realization that he too could die and that he must prioritize his own survival. One especially poignant moment is when he decides that survival justifies his stealing clothes from corpses.