DEAR ABBY: What do you do when your daughter's ex-boyfriend continues to call you and ask for information about her personal life and activities?

After two years of dating, "Anna" ended the relationship. There were vast differences in their maturity and goals, and she had been unhappy for some time. Our family always welcomed him into our home, and I think because of this, he feels that I'll sympathize with him.

I have told him that I cannot and will not give out information that is no longer his concern, yet he continues to call. He cries and tells me how much he loves her, that he cannot live without her. This is beginning to frighten me, as I have seen him driving down our street late at night with the headlights turned off. He is not a teen-ager; he is 24. My daughter insists that he would never harm her, but his denial of reality makes me very concerned. -- A WORRIED MOM

DEAR WORRIED MOM: The next time he calls and cries, tell him that the signals he's sending out are not those of "love" but obsession. Tell him that he has been seen driving by with his lights off, and it's not a sign of devotion; it could be considered stalking. Explain that you are concerned about him because his behavior isn't normal, and if he's unable to accept reality, he should seek professional counseling. If he persists, consider getting caller ID -- and notify the police about the drive-bys.

DEAR ABBY: I am in love with a 44-year-old man I'll call "Mark." He was a guest for about five months here at the hotel where I work. Mark would stay here Monday through Friday and go home every weekend. His job transfer was the reason he was staying here. After he sold his home, he planned to move closer to here.

Well, a few days ago Mark got promoted, and now he has to work in Detroit. He lives only a couple of hours from Detroit, so he might not have to sell his house after all. The bad thing is, not only is Mark working in Detroit, he also has a wife.

I know this whole thing is wrong, but I love him. He promised to leave me his pager and cell phone numbers when he left, but he didn't. In fact, my boss was the one who told me that he got the new job and would never be back again. Mark and I saw each other for most of his stay here, and I miss him so much. I don't know why he left the way he did or why he hasn't even called. I have a boyfriend, and he happens to like Mark. (He doesn't know about us.)

I have Mark's address and telephone number at home, but I can't call because of his wife. I'm in the process of making plans to move to Detroit just so I can be near him. Abby, I love Mark and will do anything just to see his face and hear his voice -- even if it's for the last time. What should I do? -- MISSING MARK IN MICHIGAN

DEAR MISSING MARK: A man who cared about you and respected your feelings would not have left it to your boss to tell you about his promotion and the fact that he wasn't returning.

Not only are you missing Mark, you also seem to be missing the entire picture. Face it, my dear -- you've been dumped.

To receive a collection of Abby's most memorable -- and most frequently requested -- poems and essays, send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby's "Keepers," P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: Since it's the holiday season, your readers might enjoy the encounter I had with a last-minute holiday shopper years ago.

It was five minutes before closing time on Christmas Eve. I worked in the lingerie department of a major St. Louis department store. The regular employees were balancing and closing their cash registers, so I was the only seasonal employee left on the floor. As the closing announcement was sounding, my supervisor directed me to wait on a young man who had hurriedly entered the department.

To each of my questions regarding cost, size, style or color, his reply was, "Doesn't matter. Just one of everything that amounts to $200." I then selected panties, slip, nightgown and a negligee in medium sizes and neutral colors. After boxing the items and ringing up the sale, I wished him a happy holiday and hoped that his wife would like the gifts.

He replied: "Doesn't matter. She'll return them unopened; she just wants to see the sales receipt to see how much I spent on her."

Abby, the entire transaction took 15 minutes and gave me a humorous story to tell my waiting family. The gifts I received that year were praised to the skies and not one was returned. A lesson learned. -- SHIRLEY IN CAPE CORAL, FLA.

DEAR SHIRLEY: Thank you for sharing. More than a few people can benefit from that lesson.

DEAR ABBY: I liked the letter from "Knowing in the Northwest" regarding depression. However, I wish you had made the point that there is a difference between emotional depression, which usually happens in response to an unfortunate event (such as death or divorce), and biochemical depression, which is often genetic and usually requires medication to be fully treated.

The misunderstanding about the differences between these two conditions is widespread.

I have had polar depression for more than 30 years. I am doing well on medication and am very grateful for this. However, I am tired of people who do not understand that there is such a thing as biochemical depression.

People repeatedly ask what is depressing me. When I reply that I am not depressed ABOUT anything, and that the problem is biochemical, they insist that isn't possible. These same people understand that diabetics need to take insulin because their bodies do not produce or properly use it. Why can't they comprehend that there are people who need antidepressants because their bodies are lacking a chemical?

Abby, please do all of us who suffer from polar depression or bipolar depression a great service by informing the public that some forms of depression are purely medical in origin. Anyone who thinks otherwise is stuck in the misinformed thinking of 20 years ago, when getting in touch with your feelings was thought to cure all emotional ailments. I tried that. It simply didn't work for polar depression. -- ALSO KNOWING IN SUNNYVALE, CALIF.

DEAR ALSO KNOWING: I agree there is much confusion about emotional depression and biochemical depression. However, after reading your letter, I'm sure there will be much less confusion. You have explained the difference very well.

To receive a collection of Abby's most memorable -- and most frequently requested -- poems and essays, send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby's "Keepers," P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: I am a medical student near graduation. In my admittedly brief experience in the local hospitals, I have already seen the damage alcohol and drugs can wreak on a life and the many relationships it poisons. Too often it takes a dramatic, life-threatening and socially costly event to provide a patient "insight" into his problem.

In June 2000, I will receive my medical license. I wrote the following in the selfish hope that it will keep me from having to deliver this bitter news, even for just one night. The words in quotes are my spoken words. The words in parentheses are what I'm really thinking. -- HEALER IN SAN DIEGO

DEAR HEALER: The short essay you have written is sobering and thought-provoking. I hope its message will reach those who need to heed it -- and remind them to set limits on the amount they imbibe. Read on:

"I realize you must be upset, Mrs. ____." (But you can only imagine how frustrated I am by this daily occurrence.)

"I am calling to inform you of your son's admission to the hospital." (Where we still haven't figured out why people do this to themselves.)

"As I understand it, the paramedics were called" (to a party where no one was sober enough to explain what happened) "and were required to administer CPR in order to revive your son's heart." (While his friends continued their drunken reveling, undisturbed.)

"He is currently on a machine to assist in his ventilation." (Because he drank so much he stopped breathing.)

"His brain suffered a significant period of anoxia." (And if he ever wakes up, he can never have his life back.)

"His condition is serious, but he is receiving expert care." (I wish I could tell you just how worried you should be!)

DEAR ABBY: I am a strict Catholic who does not believe in "kinky" activities. It was my second date with a seemingly conservative gentleman. Everything was going well, so I felt comfortable holding hands with him -- until he proceeded to stick my pointer-finger in his mouth. We had just come from dinner, so he couldn't possibly have been hungry!

What are your thoughts on this situation? -- SHOCKED IN PITTSBURGH

DEAR SHOCKED: It could have been worse. At least he wasn't a thumb-sucker.

Never do anything you're not comfortable doing. There are men out there who will respect you just the way you are. If he's not for you, fix him up with a nail-biter. They'll think they died and went to heaven.

For an excellent guide to becoming a better conversationalist and a more attractive person, order "How to Be Popular." Send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby Popularity Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)