It was a revelation, and it happened when we were in Paris.
You've grown up.
There you were, toting Jean Paul - your fox terrier pup named, you said, after Sartre - bantering in fluid French with vendors and bakers about squab and baguettes; setting your mother straight in the bright and bustling metro system; guiding me through the zoo and the old art materials shop you knew I'd love; and helping me determine which coin was the franc.
It wasn't all that long ago I tried to interest you in a celebration at the Asia Society here in New York. You just plain balked.
Ah, adolescence. We've lived to tell our tale, but those years were tough. The contentions were, for the most part, about surface matters such as make-up, a flash of sass, your declaration that you were taking up the martial arts.
Your special qualities, which were clear, it seems, since infancy - your sensitivity, your capacity of outright wonder, your inclination to cherish nature, and your passion for fairness - helped sustain us both through your teenage years.
If I had it to do again, I'd have been more patient. I'd have listened more closely for your ''big'' questions that brewed just beneath the surface.
The crux was communication, a cliche in our times, though nonetheless a truth.
But in Paris, we were on new ground.
For one thing, your tastes had matured. You showed me the Louvre with its wonderful ancient Roman ''Galerie des Mosaiques.''
We saw the Pompidou Center with its romp of contemporary art, Musee d'Orsay, the Sorbonne, Saint Chapelle, Montmartre. Treasure upon treasure.
You commented now and then in your exuberant way, and there was depth, not to mention dry humor, in your words.
When your friend Michael joined us, I saw another side to you. Softer. No martial arts. It was delightful to observe against a background of the double rainbow we three encountered as we left Versailles.
But the changes run deeper than taste. The key, I think, is balance. I sense in you a new balance between the creative and common sense; balance between play and working hard to fulfill your dreams; balance between discretion and standing up for your values and beliefs.
And, not least, knowing right from wrong in a world that will challenge you constantly.
I write to you in these public circumstances, Alex, because I've found we aren't alone in our experiences. In a complex society, many parents are searching for answers. I've found no glib solutions, only glints of wisdom.
You've teased me about worrying too much, and I can't promise that'll end now that you've come of age. But we now have scaffolding for a renewed relationship. We have more to say to one another, more to share.
We have a future to face and to savor. Bless Paris.