When one of my nephews was about six or seven he had this obsession with a cartoon character named "Bravestarr." He even talked his mom into sewing him a costume, which he wore around the house.
What was he doing? Practicing to be a grownup. Practicing to be a hero.
The book listed above? Amazon had this to say about it: "Children choose their heroes more carefully than we think. From Pokémon to the rapper Eminem, pop-culture icons are not simply commercial pied pipers who practice mass hypnosis on our youth. Indeed, argues the author of this lively and persuasive paean to the power of popular culture, even trashy or violent entertainment gives children something they need, something that can help both boys and girls develop in a healthy way. Drawing on a wealth of true stories, many gleaned from the fascinating workshops he conducts, and basing his claims on extensive research, including interviews with psychologists and educators, Gerard Jones explains why validating our children's fantasies teaches them to trust their own emotions and build stronger selves."
The purpose of play and heroes is for children to work though certain fears and become stronger for it. When I was a kid we used to ride our bikes ten miles away, engage in dirt-clod fights, jump off of cliffs into lakes and God knows what else. I've got scars all over me. And we were better for it - braver and stronger and more confident and competent. I see much of that missing today.
Most of our education was not in school.