How involved should a parent be in the life of a teen-ager? That's the question a classroom of high-school students tried to answer when their teacher asked them to respond to a column I had written. Many of these essays expressed deep appreciation for parental involvement. Other eloquent voices, which arrived in a fat envelope, were cautionary. "Don't try too hard to be (your children's) best friend," advised one student. But, she added, "don't leave them alone."

That's a mantra that runs through these essays: Don't leave them alone.

"There has to be a happy medium somewhere between apathy and totalitarianism," one student wrote. Finding that balance isn't easy.

"Some children have sort of a natural independence," one teen-ager wrote. "On the other hand, there are people like me. Ever since I was young, I've had trouble taking initiative and doing things on my own. For example, I got scared to death the first time someone told me to call for a pizza delivery." She stressed that parents need to be involved, but in a way that fosters independence.

Another girl expressed pride in her self-reliance.

"I am the daughter of a strict Chinese mother and traditional, easygoing American father," she wrote. "I get the best of both worlds. I've never had a breakfast, lunch or dinner made for me, except of course on special occasions. I even shop for the groceries every Saturday. All that I'm dependent on my parents for is the roof over my head and some financial support, even though I hold down my own job. Although I am extremely autonomous, I still need to tell my parents about my whereabouts. My parents are preparing me for the real world. They've never babied me."

But even the most independent teen-agers say they want to be monitored, although they approach this idea cautiously. One student offered this advice to parents of teens: "Show them that you care, without interrogating them. In some ways, you should be deceptive when checking up on them, on their peers, scholastic progress, and their interests. This is difficult, because you do not want your children to know you are checking up on them."

Several students warned parents to be careful about assumptions.

"Don't let yourself fall into believing that your kids would never do anything wrong because when they do you'll have a `triple heart attack' like my mom once said," one student wrote. "You'd be surprised at how much mischief your kids have already been through but that you don't know about." That's not a comforting thought, but the point is important: There's a fine line between high and unrealistic expectations.

But the mantra still applies: Don't leave them alone.

Some of the essays, in the form of letters to parents (probably never to be sent), were bathed in normal adolescent angst, but others were drowned in pain.

One teen-ager, who has run away before, wrote: "When I was entering adolescence I found that my mother was deserting me because she never did the things that she used to do, although it wasn't because she felt that I was old enough -- it was due to her promotion at work. She never realized that my rebellious behavior was so that she could see me."

Another student wrote: "Our relationship has never been good. Now it has culminated in my moving out." She accepted some of the blame, then added, "But the two of you made mistakes. The first of these is a lack of involvement. I could never share my feelings with you or I would be judged and yelled at. When I did share my personal life with you, you later used it against me. I came home with trophies you didn't care about. I was told to put them in my closet because they cluttered my room.

"All I know is my friends gave me the love and support I did not have from you. They never called me a slut, bitch or tramp. It is too late for me. But there is a lot of time for (your other child). Please, listen to me this once, for her sake."

And there were other letters filled with longing.

"Dear Dad . . . Do you actually know how many times you've left me?" another letter read "From ages 7 to 14 I stayed at neighbors' houses, day after day after day. And even at 15 to 17 you leave me at home for weeks on end. Even when you are home, I see you about once or twice a week! What kind of relationship is that? Leaving me alone a lot has made me an extremely independent person. Thank you. At least I know I won't be homesick while at college. You said, `You just want attention' even when I told you I was hurting inside. Damn right I just want some attention -- for once!

"If you only knew how lonely I really am. I've been living in my shell for a long time and I think I want to get out but the shell is so thick and calloused. How can I do it? Do you even know what my favorite color is? You lost me somewhere and you can't get me back."

Look for the balance. But don't leave them alone.