DEAR MISS MANNERS: My sister-in-law has adopted an alternative lifestyle that embraces a range of unsubstantiated psychological, medical and scientific myths as proven fact. She makes it clear her beliefs and knowledge are vastly superior to the rest of us and often uses our dinner table as an opportunity to educate us in a rather condescending manner on a variety of subjects.

Once she begins, she will dominate the conversation throughout the meal, essentially turning it into a lecture. We all take offense, but especially my daughter, who has a Ph.D., is currently conducting advanced research on viruses at a leading Ivy League university. She has left the table rather than start a fight -- but that ruins the family gathering for the rest of us.

My daughter and her aunt typically see each other but once or twice per year. The preaching leaves little time for the rest of us to have family chitchats. What would be a polite way to address the problem with my sister-in-law? Subtle diversions in conversation do not seem to get the message across.

GENTLE READER: Your sister-in-law is engaged in two objectionable activities at once, neither subtle. Miss Manners notes this not to express admiration for her efficiency, but because it will be easier to tackle them separately.

The first is spouting nonsense; the second, monopolizing dinner-table conversation. The former will be difficult -- perhaps impossible -- to fix. But as you see her infrequently, fixing the latter may be enough.

The solution is an explicit rule that such topics are off-limits at family gatherings because of a fundamental and implacable difference of opinion. Explain to your sister-in-law (or your brother) that the alternative will lead to such ill will that family dinners will no longer be possible.

DEAR MISS MANNERS: I attended a lovely wedding -- where no one seated more than a few rows back could hear any part of the service, because either the microphones were malfunctioning or they were not being used properly.

If this had happened at a business meeting or a more casual event, someone would surely have called out “Louder!” or “Can’t hear!” but obviously this would not be appropriate at a more formal occasion.

No one “in charge” -- meaning the couple’s immediate family, the officiant, photographer, wedding party members --seemed to be aware that the rest of us couldn’t hear what was going on.

GENTLE READER: Yelling at a speaker is not proper etiquette in any setting, though it is, as you observe, a common occurrence.

For business meetings or casual gatherings, Miss Manners counsels members of the audience to raise their hands as if in class. You may then call out your request for increased volume -- without waiting for the technicality of being recognized by the speaker.

More active measures are necessary when you cannot interrupt the proceedings: Get up and find someone to whom the need can be conveyed, in this case a member of the family, the wedding party or the church staff -- preferably one not actively engaged in the ceremony.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: My husband was a lawyer and is now retired. Several times a year, people ask him to talk to their children who are considering applying to law school.

Miss Manners, my husband hated every minute of his law career and doesn’t mind describing why. (The several years when a credible source threatened to burn down our house -- they had burned down others! -- was probably the worst.)

My concern is that there are perfectly bright, perfectly capable young people who would make perfectly good lawyers but, because they ran across my husband, went into some other field that they ended up hating even more than they would have hated law. Should I try to get him to moderate his position? If so, how?

GENTLE READER: Why do you think it necessary to protect possible future lawyers from hearing about difficulties that may be associated with the profession? Those who ask your husband probably ask others, and the wider the view they get, the better.

Besides, Miss Manners recalls asking an excellent drama teacher why she was advising her most talented student not to seek a career as an actress. “Because if that discourages her, she doesn’t belong in the theater,” was the reply.

DEAR MISS MANNERS: Over the past few years, I have noticed that two of my dear friends never check their mail. Their mailboxes are often so full that mail gets returned to sender as “unclaimed.” I receive back over half the mail I send them.

In the past, I have re-sent formal thank-you notes, but these have been returned often enough that I am irritated and don’t want to waste another envelope and stamp on the hope that they will have managed to check their mail.

Is there any sort of two-strikes-and-you’re-out rule regarding thank-you cards? Should I just send them e-cards instead? Or try to deliver in person?

I feel like I shouldn’t have to bear the onus of their failure to check their own mailboxes, but if that is the most polite course of action, I can grin and bear it a few times a year.

GENTLE READER: As you are diligent enough to write letters of thanks -- you may be shocked to hear that not everyone does -- it does seem unfair that you should also be responsible for retrieving them as well.

But it has become a factor of modern life that not everyone uses the standard forms of communication. Some do not answer their telephones. Some rarely check their email. Some do not text. And your friends do not empty their mailboxes.

Miss Manners does understand that all of these venues may be so choked with junk that people have come to ignore them. Still, it is a nuisance.

As you have only two such friends, you should just ask what is the best way to reach them. But soon we will all have to keep records of who actually checks what.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: I share a small home with two family members, and I am struggling with the question of where I may go to compose texts or emails without a) being rude, or b) being disturbed. I know the answer is not “the dinner table.”

However, may one compose texts or emails on the family couch, and if so, should others refrain from attempting to engage the person composing texts or emails in conversation?

I know of one family in which adults hide in one of the bathrooms if they wish to compose emails. However, we have only one bathroom, and it would be inconsiderate to use it this way. Further, it doesn’t seem that it should be necessary.

If each of us had a personal office (or even if we had one shared office), that would be an ideal solution, but again, our home is small.

GENTLE READER: And that is why there are so many coffee shops, where patrons sometimes respect the need of others to pay attention to their laptops.

Not being in a position to run around your house searching for a quiet nook where you will not disturb others or be disturbed by them, Miss Manners can only make guesses. Your bedroom, but not during sleeping hours if it is shared? The kitchen, when mealtime is not approaching? For that matter, why not the dining room when it is not being used for dining?

But what is she doing in your house? You have two people right there who know the layout and have something to say about what constitutes disturbances. All people who share living space, whether as roommates, relatives or boarders, have to negotiate its use with one another without generalized rules from the outside.

DEAR MISS MANNERS: My niece got married a couple of years ago for the second time. Her husband-to-be had never been married. They chose to have a casual wedding, but they invited at least 100 guests, primarily their friends on both sides of the family and a few chosen family members.

Prior to the wedding, I sent a wrapped gift from their wedding registry and a large bottle of wine per the invitation as a contribution to the bar. I included a card with the gift attached to the package.

We felt completely ignored at the wedding and were never introduced to the new husband. No effort was made by the bride and her new husband to walk around speaking to guests. In addition, I never received a thank-you either verbally or in writing from my niece and her new husband.

I’ve been steamed over this ever since. I’ve remained silent now for years. What do you suggest someone should do, if anything, when this sort of thing happens, other than grin and bear it?

GENTLE READER: When Miss Manners hears the word “casual,” she shudders. It no longer means “informal,” which is a legitimate style. Rather, it has come to mean “not bothering to perform even the most common courtesies.”

But your experience was two years ago. By now you should have put in practice the only sensible response, which is to decline any invitations to their birthday parties, re-enactment ceremonies, baby showers, or whatever else they may have devised for assembling people they will then ignore.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)