Some people get all weepy when their children leave home for college, but not me. Children are supposed to grow up and move away. It's no big deal.

So I shed no tears on the final week of summer vacation when I drove my daughter Molly to the University of Pennsylvania, where she and a roommate will live. Their dorm room would fit two Volkswagens and a wheelbarrow. The air inside is suffocating. The decor is Kmart. The carpet is septic. The place reminds you of those hotel rooms in the movies where stubbled gangsters in ribbed undershirts and fedoras hide from the fuzz while a neon sign blinks outside. Molly's walls are a shade of paint that Sherwin-Williams could market as "Dingy Yellow." Or "You'll-Never-Take-Me-Alive Copper."

Molly took one look around and was giddily happy.

So I am happy. That is the way it is supposed to work, and it is working fine, in my case.

Molly's roommate is from Chicago. Within minutes of meeting, the two women were bouncing around campus, their lives already jubilantly intertwined. It seems odd to use this term, women. I know it is the accepted designation for 18-year-old human females, the legally correct word, a word sanctioned by the restroom doors at some of the nation's finest institutions of higher education. But until a few days ago, or so it seems, I was wiping strained prunes off this woman's chin.

I am disoriented, but not dismayed. The whole point of being a parent is to reach this moment. You spend 18 years encouraging your daughter to be independent, even headstrong, and when she strides away confidently on her own you should feel good. And I do.

The University of Pennsylvania is in Philadelphia, and on the day I arrived the local newspapers reported that a sicko was stalking the streets. He is believed to have raped several women and killed at least one. Molly is unworried; when you choose to live in a big city, she informs me, you must accept certain risks.

Molly chose this city, and worked hard for it, and got it. My daughter usually does what she needs to get what she wants. When she began to drive, she angled for a deal: We would allow her to come and go as she pleased, within reason, so long as she used good judgment, never lied about her whereabouts and maintained high grades. She did all those things, and a deal was a deal. So there was many a night when Molly came home after our bedtime, and that was okay with me. I was comfortable and confident as I lay there downstairs on the couch, inches from the door, beneath an old clock ticking loudly in the stillness, awaiting her step on the stair. I am also comfortable and confident about her safety in Philadelphia.

I have not told Molly to be careful out there, because she already knows it, and besides, no one tells Molly what to do. To use the ladies' room at her dorm, she must walk down a long hall and up a flight of stairs. There is a restroom right across from her room, but it is labeled for use by men only. Instantly, Molly announced that she would regard this designation to be optional.

For the last two years, Molly has volunteered at a firehouse, dressed in a baggy blue uniform, riding the ambulances. She wants to be a doctor, and at the youngest allowable age she became a licensed emergency medical technician. One night she came home from work with blood on her, and a story: A car had hit a bridge abutment at high speed, and people were gravely injured. Molly had been ordered to ride to the hospital with a man whose leg was snapped in two at the thigh; her job was to be a human traction splint, tugging his bones into place as he moaned and whimpered.

She was not yet 17. Her mother and I hugged her and asked if she was okay.

"Okay?" she said. "This was the greatest day of my life."

Molly is small and pretty, and from time to time she took some crap from the guys at the fire station, the usual bawdy banter and good-natured lechery. But when Montgomery County mounted an official investigation into alleged sexual harassment there, she declined to be interviewed. I asked her why. "It's a firehouse, Dad," she said, rolling her eyes.

Her eyes are slightly blue but mostly gray, precisely the color of the door of van Gogh's bedroom at Arles. A reproduction of that painting hangs on the wall of Molly's bedroom, which I am pacing right now. The room almost echoes. It is half empty, and tidy for the first time in my memory because her mother spent hours after Molly left fanatically cleaning and re-cleaning it, explaining all the while how she, too, is untroubled by Molly's departure. It's no big deal, we agreed.

I notice that Molly has not taken her baseball glove. The stitching is frayed, the knots are undone, and part of the heel has been gnawed by our dog. I kept offering to buy her a new one, but she refused, explaining that a glove is supposed to be old and weathered.

Molly never cared much for sports until a few years ago, when she and I began watching Yankees games together. In the beginning she understood only the rudiments, but it's gotten so she can tell you the best pitch on which to execute a hit and run with a lefty at the plate and one out.

Molly thinks certain rules of baseball should be changed to make the game better. She calls her new, improved version "Mollyball," and here is how it works: When a fielder makes a valiant lunge at a ball, even if he misses, or when a player runs really hard to first base, even if he is out, he is awarded a point for effort. If you accumulate enough points, your team gets an extra run. Also, if a player slides and gets his uniform dirty, he is afforded reasonable time to go to the clubhouse and change. Also, really handsome players like Derek Jeter get an extra strike. Also, there are trees in the outfield. Because they look nice.

Playing catch with me in the back yard, Molly learned to snare anything within her reach. She has a good, strong arm. As we slung the ball back and forth, I invented bases-loaded-bottom-of-the-ninth clutch fielding scenarios, the way fathers and sons have done forever. Molly got into it, or pretended to for my sake.

I always felt Molly and I were particularly close, but she kept me guessing, right from the get-go. When she uttered her first word, she pointed at me and said "da-da." I was elated. A few seconds later, she said "da-da" again and pointed at the toilet.

Sometimes it is that way with children. You never really know what they are thinking. You try to give them no reason not to love you, and hope for the best.

Molly and I haven't played catch for a while, because she was preparing to leave for college and had friends to visit and things to do. Experts will tell you that a child about to leave the home will sometimes become cold and detached, and even precipitate fights with her parents. No malice is intended; they are unconsciously trying to create a distance that will make the leaving easier. Molly did this. Like everything she does, she did it magnificently.

When I kissed her goodbye at school, I told her to take care and she told me to take care, and that was that.

Back home, I picked up a baseball and her ratty old glove and went out in the back yard. It was starting to drizzle, which was good because we needed the rain. I began to play catch with myself, underhanding the ball and basketing it like Willie Mays.

Each time, I threw it harder, and when I could get the ball no higher I began throwing overhand, again and again, stupidly hard, trying for greater and greater height even after my shoulder began to ache. I was grunting with each throw, and finally the ball was so slick with rain that I lost control of it and it sailed away and came down in the middle of a thick stand of bamboo on the edge of my property. The treetops are dense with foliage, and the ball was swallowed up. It didn't hit the ground. It probably caught on something: a latticework of branches, maybe, or a squirrel's empty nest.

It must still be up there. I never found it. It's no big deal.