We sit at the end of the pier, just the two of us, listening to the sound of water lapping against the docked boats, watching the sun disappear behind the trees which define the bank on the opposite side of the river. Bit by bit in the fading light, we catch the delicate tracery of leaves and branches blur and fade until the shoreline is merely a dark, indistinct mass.

On this Labor Day weekend we are saying, my 14-year-old son and I, goodbye to summer. Goodbye to summer and, I suspect, to a number of other things as well.

For I am experiencing, no doubt about it, a sense of Chekhovian loss about this son as I observe his passage from boyhood to adolescence, a journey which inevitably -- and appropriately -- must take him away from me. At times it seems I can almost hear them hacking dowm the cherry orchard in the background.

Breaking away, letting go, finding his own space. The roller-coaster symptoms of adolescence are all there: One day he is edgy, impatient, restless, bored, no good at anything; the next, wildly happy, productive, on top of it, confident, capable of accomplishing anything, full of plans. My son is new to all of this, clearly an amateur at 14, but time and hormones are closing in fast.

First you'd have to see him. He is taller than I am now, a gracefully muscled boy with sun-streaked hair and blue eyes who lives in jeans and T-shirts with messages emblazoned across the front. When he cracks a grin, the wattage from it could light up Yankee Stadium. Fiercely independent, a fanatic about fairness, he appears to be doing a pretty good imitation of a cool, self-confident teen-ager.

But his voice betrays his laid-back pose; it is totally out of control. At times high and reedy, it suddenly without warning plummets down the length of some imaginary scale, completely off-key, sliding up and down, desperately trying to land somewhere. What you hear is something like a beginning clarinetist at practice: uncertain of the notes, the results not yet a piece of music, but the promise of something, a melody which will come with time.

His summer accomplishments, both physically and intellectualaly, leave me in a state approaching awe. In just three months, he has sprinted through astronomy, mountain climbing, carpentry, sailing, metal working, Tolkien and photography. The adrenalin of adolescence is clearly in high gear and the thought presents itself to me: If he can do all this in three months, what, in God's name, will he accomplish in six months or a year? It leaves me dizzy, pleased and more than a little nervous.

My son is dreaming of the world, of being free, of inhabiting his own life. He is full of the freshness, the innocence, the promise which goes with beginnings. Looking at him I think, was I ever like this?

And then the pieces of my own life, the fragments of memories pile up, glisten, beckon me back seductively and, before I know it, it seems like only a moment ago and I too was 14, planning to learn Greek, wanting to become a heart surgeon, dreaming of making a million dollars, yearning to fall in love and vowing to myself that I would become totally independent and self-sufficient. As nearly as I can recall, I planned to do all of this over a two-week Christmas vacation.

Remembering what it is like to look out at the world through 14-year-old eyes helps me to understand my son. But it can't quite dull the pain of relinquishing a central role in the life of a child I love, of being quietly, but inexorably, forced out of the center of his world and onto the sidelines.

So we sit sharing this twilight, both preoccupied by the future. And then my son, his eyes squinting into the last glowing rays of the setting sun, his face gentle and serene, tells me in a rushing soliloquy, of his life's plans, his dreams, his fears and where he'd like to go to camp next summer. In a rare burst of intimacy, he lays his whole life out in front of me, like a gift. If there is a hint of betrayal in his plans, all of which revolve around grasping his own life and moving on, I try not to notice. For I am moved by his openness and vulnerability and, more than anything else, I want to be able to wish him well.

It all sounds so clean, so simple, so pure, so possible -- these dreams he tells me about. So convincing is he in his optimism and enthusiasm that I am totally won over to the side of innocence. Listening to him, I momentarily lose my balance, suddenly doubting myself and wondering whether anything I know is really worth knowing.

Quiet now. I study my son's profile, set like a coin against the sky. Without warning a fierce wind of unconditional love blows over me and I long to take his large, bony, boy's body in my arms and smooth his hair from his forehead and hold him like a child again. Hold him against his leaving, against the start of his journey.

But, of course, I don't.

What's that lyric the Beatles sang back in the '60s? Ah, yes, I remember. "Hello, hello. You just say goodbye, I say hello."