“The Wizard of Oz” fills such a large space in our imagination. It somehow seems real and important in a way most movies don’t. Is that because we see it first when we’re young? Or simply because it is a wonderful movie? Or because it sounds some buried universal note, some archetype or deeply felt myth?

I lean toward the third possibility, that the elements in “The Wizard of Oz” powerfully fill a void that exists inside many children. For kids of a certain age, home is everything, the center of the world. But over the rainbow, dimly guessed at, is the wide earth, fascinating and terrifying. There is a deep fundamental fear that events might conspire to transport the child from the safety of home and strand him far away in a strange land. And what would he hope to find there? Why, new friends, to advise and protect him. And Toto, of course, because children have such a strong symbiotic relationship with their pets that they assume they would get lost together.

This deep universal appeal explains why so many different people from many backgrounds have a compartment of their memory reserved for “The Wizard of Oz.” They’re touching on the key lesson of childhood, which is that someday the child will not be a child, that home will no longer exist, that adults will be no help because now the child is an adult and must face the challenges of life alone. But that you can ask friends to help you. And that even the Wizard of Oz is only human, and has problems of his own.

“The Wizard of Oz” has a wonderful surface of comedy and music, special effects and excitement, but we still watch it six decades later because its underlying story penetrates straight to the deepest insecurities of childhood, stirs them and then reassures them. As adults, we love it because it reminds us of a journey we have taken. That is why any adult in control of a child is sooner or later going to suggest a viewing of “The Wizard of Oz.”

Judy Garland was a luminous performer, already almost17 when she played young Dorothy. She was important to the movie because she projected vulnerability and a certain sadness in every tone of her voice. A brassy young child star would have been fatal to the material because she would have approached it with too much bravado. Garland’s whole persona projected a tremulous uncertainty, a wistfulness. When she hoped that troubles would melt like lemon drops, you believed she had troubles.

Her friends on the Yellow Brick Road (the Tin Man, the Scarecrow, the Cowardly Lion) were projections of every child’s secret fears. Are we real? Are we ugly and silly? Are we brave enough? In helping them, Dorothy was helping herself, just as an older child will overcome fears by acting brave before a younger one.

The actors (Jack Haley, Ray Bolger, Bert Lahr) had all come up through a tradition of vaudeville and revue comedy, and played the characters with a sublime unself-consciousness. Maybe it helped that none of them knew they were making a great movie. They seem relaxed and loose in many scenes, as if the roles were a lark. L. Frank Baum’s book had been filmed before (Oliver Hardy played the Tin Man in 1925), and this version, while ambitious, was overshadowed by the studio’s simultaneous preparation of “Gone With the Wind.” Garland was already a star when she made “Wizard,” but not a great star–that came in the 1940s, inspired by “Wizard.”

The special effects are glorious in that old Hollywood way, in which you don’t even have to look closely to see where the set ends and the backdrop begins. Modern special effects show *exactly* how imaginary scenes might look; effects then showed how we *thought* about them. A bigger Yellow Brick Road would not have been a better one.

The movie’s storytelling device of a dream is just precisely obvious enough to appeal to younger viewers. Dorothy, faced with a crisis (the loss of Toto), meets the intriguing Professor Marvel (Frank Morgan) on the road. She is befriended by three farm hands (Bolger, Haley and Lahr). Soon comes the fearsome tornado. Then, after the magical transition to color, Dorothy meets the same characters again, so we know it’s all a dream, but not really.

There are good and bad adult figures in Oz–the Wicked Witches of the East and West, the Good Witch Glinda. Dorothy would like help from her friends but needs to help them instead (“If I Only Had a Brain,” or a heart, or nerve, they sing). Arriving at last at the Emerald City, they have another dreamlike experience; almost everyone they meet seems vaguely similar (because they’re all played by Morgan). The Wizard sends them on a mission to get the Wicked Witch’s broom, and it is not insignificant that the key to Dorothy’s return to Kansas is the pair of ruby slippers. Grownup shoes.