DEAR ABBY: In the late '80s, I worked in the kitchen of a catering company. The hours were long, the work was hard and the pay was minimal.

One day, the boss posted a letter on the bulletin board in the kitchen from a customer who was delighted with the food, service and professionalism of our company. All of the employees were thrilled that someone took the time to write a letter to compliment us.

That letter set the tone for a very long time. Whenever we felt overworked and underpaid, all we would have to do was go over to the bulletin board and read the letter. Our spirits and morale were automatically boosted.

Since then, whenever I encounter a product or service that I really enjoy, I take the time to let them know it -- in writing.

If there is a company that is doing something right, a product that you really enjoy or a person who is an angel in disguise, take the time to express to them, preferably in writing, what you feel. Encourage them to keep up the good work, tell them what they do is important, and thank them. It will make their day -- or year.

To all the bosses out there: Don't keep the letters in a file; put them where everyone can see them! -- NEW ORLEANS READER

DEAR READER: I couldn't agree more. A thank-you note or written word of praise takes so little effort -- and yet it can make a tremendous difference. The written word is a powerful medium that can be enjoyed over and over again, and speaks as eloquently of the writer as it does the subject about which is being written.

DEAR ABBY: After 34 years of marriage, I learned that my husband was cheating with a woman three years older than our son.

The hurt was terrible and the embarrassment was horrendous. Not as much for me, but for people who did not know how to console me. With a death, friends can be sorry and there is closure. With a divorce, people do not know what to say.

My method for dealing with this was with humor. People were well aware of my hurt, but when I replied, "He got the bimbo; I got the tractor," they were able to laugh and their discomfort dissipated. My advice is to find a catch phrase that lightens the situation. You'll still hurt and mourn, but your friends will be much more comfortable. The sooner you laugh, the sooner you heal. -- MERILYN IN HOLLY, MICH.

DEAR MERILYN: Wise words, indeed.

DEAR ABBY: You were wise to advise the concerned family members to seek help for the sister whom the mother was avoiding because of her newly unpleasant behaviors. However, you were incorrect in your statement that she may have a mental illness or depression. Abby, depression -- along with a whole host of other neurobiological brain disorders -- IS a mental illness. -- CYNTHIA HAMMER, PRESIDENT, NATIONAL ALLIANCE FOR THE MENTALLY ILL, PIERCE COUNTY, WASH.

DEAR CYNTHIA: Thank you for pointing this out. Readers, NAMI (the National Alliance for the Mentally Ill) is a nonprofit organization of more than 190,000 members that advocates for research and services in response to major illnesses that affect the brain. Anyone interested in learning more about mental illness is encouraged to call NAMI's helpline at (800) 950-6264 or visit the Web site at www.nami.org.

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.)

DEAR ABBY: In past months, some of the letters in your column have dealt with forgetfulness and aging. I would like to inform your readers about a research study designed to address the issue of memory loss found in normal aging compared to that seen in early Alzheimer's disease.

The Memory Impairment Study is taking place at 60 to 80 sites across the United States and Canada, and holds promise for medical intervention against the development of Alzheimer's disease. The study will investigate two treatments that will, we hope, lessen the likelihood of developing Alzheimer's disease in people with a condition known as mild cognitive impairment.

Mild cognitive impairment refers to a type of memory loss beyond that which is expected during the course of normal aging. Symptoms typically include forgetting recent experiences on an increasingly frequent basis. Persons with mild cognitive impairment are otherwise normal, engage in the usual activities of daily living, and do NOT have a diagnosis of dementia or Alzheimer's disease. Nevertheless, it appears that such individuals are at higher risk for developing Alzheimer's disease.

For the study, we are looking for men and women between the ages of 55 and 90 who are in good general health but are forgetful for their age. They must have a partner who is familiar with them and can accompany them to their clinic visits. The study will run for three years. Clinic visits occur approximately every six months. We will be testing two treatments in comparison to a placebo (an inactive pill).

Volunteers for this study are key to helping us provide hope for the millions of individuals affected by Alzheimer's disease.

We greatly appreciate your support for research in Alzheimer's disease and hope your readers will contact us if interested. -- RONALD C. PETERSEN, M.D., DIRECTOR, ALZHEIMER'S DISEASE RESEARCH CENTER, MAYO CLINIC, ROCHESTER, MINN.

DEAR DR. PETERSEN: Thank you for a fascinating letter. I'm sure that many will be interested in the direction that the latest, cutting-edge research is taking in the search for a cure for Alzheimer's disease. As the population of our country ages, it's a problem that will affect an increasing number of individuals and families.

According to the latest figures from the Alzheimer's Association, approximately 4 million Americans have Alzheimer's disease. Fourteen million Americans will have it by the year 2050, unless a cure or prevention is found.

Readers can obtain more information about the study by calling (888) 455-0655 or by visiting the Memory Impairment Study Web site at: www.memorystudy.org.

DEAR ABBY: Some of my friends tend to be a bit immature at times, about both serious and minor situations. I try to give good information if they don't know what to do, or if they're considering something foolish to get through their crisis.

Is there a certain approach or a time that is best to give out my information so that they take it as seriously as I would take it? -- KELLY IN PORT WASHINGTON, N.Y.

DEAR KELLY: Yes. The most unwelcome advice is that which is unasked for, so volunteer your information only when asked. The exception would be a life-threatening situation.

CONFIDENTIAL TO MY JEWISH READERS: Happy Hanukkah, one and all!

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: After reading your column about outrageous mothers-in-law, I had to write. When I was 17, I married my high school sweetheart. He was only 20. We were entirely too young to get married. However, his mother never said a negative word about it. In fact, she was our most ardent supporter.

The following year, we had a baby boy. We were too immature to have children, but my mother-in-law never said an unkind word. She was extremely kind and generous to my son and to me as well. She never once criticized the way I took care of the baby. When she came to visit, she asked me nicely what I wanted her to do, and then she did it. When I think of this now, it brings a smile. I was only 19 and knew nothing about babies, but still she respected my wishes as the mother of this child. If she had a negative opinion about me, she kept it to herself.

After a few years, the marriage fell apart. The subsequent divorce and custody battle got very ugly. My mother-in-law never took sides.

I am now happily remarried and live about 3,000 miles away from my former mother-in-law. My former husband has also remarried. Neither of us has had any more children, so my 12-year-old son is my former mother-in-law's only grandchild. He visits her every summer, and I keep her up-to-date as much as possible about his activities via e-mail and pictures.

Sometimes people are curious about why I work so hard to keep this connection to my ex-husband's family. After all, according to the world's expectations, we're supposed to "hate" each other, right? Wrong! This lady is a gem. She's a sterling example of how people should treat each other.

She and I had a long talk this summer about this very subject. I told her that I do not "own" my son. He's part of her, too. And I would be doing a grave disservice as a parent to deny my child the gift of knowing this wonderful grandma. I only hope that someday I will be as terrific a mother-in-law and grandmother as she is. -- RACHAEL IN CALIFORNIA

DEAR RACHAEL: I'm sure you will be -- because you fully appreciate the maturity, generosity and diplomacy that are required to fulfill those roles. Many people could take a lesson from your former mother-in-law.

DEAR ABBY: I read with interest the letter about checking to see that a security whistle is in working order. Many years ago, I had a persistent obscene caller. Hanging up on him did not dampen his enthusiasm, so I decided to blow a shrill whistle during his next call. As expected, he called late one night, so I grabbed the whistle and began to blow.

Instead of making a shrill noise, the whistle made an odd rattling sound. Undaunted, I continued trying to whistle -- but I began to laugh at the pathetic noise. A moment later, the caller asked in an incredulous voice, "What on earth is that noise?" I explained, laughing, "I'm trying to blow a whistle in your ear!" With that, he howled with laughter, hung up and never called back. -- STILL LAUGHING IN DALLAS

DEAR STILL LAUGHING: Congratulations. Even though the whistle malfunctioned, you succeeded in "blowing off" the obscene caller. That's a victory.

To order "How to Write Letters for All Occasions," send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Letter Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)