Miss Manners' Basic Training :
The Right Thing to Say
Yes, this book is absolutely unnecessary for those who understand the principles of consideration and tact (which follows from consideration, actually). I don't know when honesty seemed to have become the principal virtue of life -- many people seem to think that the "honest" bit of "brutally honest" outweighs the "brutal" part.
Guess what. It doesn't. And Miss Manners tells you why.
This slim volume would probably not stop the tactless person from informing a young, grieving widow, at her husband's funeral, that her mother-in-law must feel this more deeply than her, for the death of a child is worse than the death of a spouse. Any person who thought for a moment would realize this is an extremely thoughtless thing to say. However, this may come in handy for the parent who is trying to come up with arguments for =why= their teenagers shouldn't say certain things. And it's definitely helpful for the people who are trying to be polite in the face of unbelievable rudeness (like the event I mentioned above.)
Miss Manners can be extremely cutting to those who deserve it -- those so self-centered that they care not what effects their words will have on others.