What is the theme in The Painted Bird by Jerzy Kosinski?

The main focus of this semi-autobiographical novel is the tracing of the main character's coming of age in an Eastern European country during World War II. After the war begins and he is separated from his parents, he spends the remainder of the book trying to survive the brutal conditions he faces in various villages in which he lives. During this journey, he learns important lessons about himself and human nature in general.