I have three sons. My middle guy, Luke, is four years old and as sweet and malleable as they come. Yesterday he came home from school with a T-Rex tooth. He was so excited as he told the story of where it came from and how he had found it. He tucked it carefully under his pillow before bed and made sure that it was transferred into his backpack this morning. It has become his prized possession, at least until the next novelty comes along.

Luke's younger brother, Charlie, is three. He is rough, stubborn, highly opinionated and very funny. He parrots everything he hears and imitates everything he sees. Luke's older brother, Max, is almost seven. But he might as well be seventy for all of his worldliness and insight. As I suspect is the case with most siblings, Luke is annoyed by his younger brother and utterly fascinated by his older. Luke's favorite place to be is wherever Max is.

Despite the unimaginable joy that Max has brought me, raising him has been a challenge. His is my first baby, so I navigate unknown and murky waters with him. But the ports that I was hoping to find have not offered quite the rest I was expecting. I was looking forward to the magic of his childhood, to his unquestioning acceptance of certain fantastical things. But that big ol' brain of his has made him accelerate through some of the best parts of childhood. While he has not, for example, explicitly denied the existence of Santa Claus, I am fairly certain that he no longer believes in him, if he ever did at all. I think he figured out a while ago that the whole premise just doesn't make sense. Like his father, Max is an engineer who places a premium on reason, order and discipline. That doesn't really leave a whole lot of room for magic.

Max and I both knew, of course, that Luke's recent acquisition was not a T-Rex tooth but rather a carefully molded piece of clay. The product of the endless patience and creativity of Luke's teachers, who see to it that every day in their classroom is an adventure for their little people.

I was so nervous when Luke showed the tooth to Max, worried that Max, with his literal and matter-of-fact understanding of the world-- would tell his younger brother that the object in his hand was no more a dinosaur tooth than the plastic food that he prepares at his toddler kitchen is edible. The news would not be delivered with any ill-intent, of course, but rather with a genuine sense of responsibility to make sure that Luke's perception of things is grounded in reality. Max, it seems, has long since grown out of that stage where childhood imagination trumps common sense. When Max himself was four years old, he came home from school with a dinosaur that had been cut out of construction paper and glued with tiny pieces of dried pasta. It was a triceratops, my favorite, which is why Max had selected it. The teacher had told his class that the little pieces of pasta were the dinosaur's bones, but Max was not to be convinced. He handed it to me with a proclamation that the article in my hand was nothing more than a rendering of a dinosaur. There was nothing real about it.

So yesterday, I held my breath when Luke showed Max-- his adored older brother--the T-Rex tooth that he found at school. I waited for Max's response, knowing there wasn't time or opportunity to coach him on what to say. But to my immense pride, Max participated in Luke's joy. He congratulated him on finding such a treasure and assured him that such fossils were exceedingly rare. Luke's face lit up. As Luke ran out of the room to find his next audience, Max turned to me and offered up an impossibly sweet smile.

"Mama," he said to me. "We have to make sure that Lukie believes for as long as possible."

And that, I am only just now realizing, is a little bit of magic.