Sure, it tells you all the proper forms. And some situations are awkward, so guidance in what to say is nice to have. For example, how do you offer condolences to a friend who's suffered catastrophic monetary loss?
Although the blow has been a severe one, there is the great consolation in knowing that your conduct has gained the ungrudging praise of everyone.
My dearest Mabel,
....I was so glad to get your letter yesterday and to hear that you are quite well. Aunt Jane was here yesterday and asked after you very kindly. She says they are all going to Montreal for August. How is Elsie Fielding? Her mother says she is thinking of going to Vassar when she leaves. I suppose she is very clever. Do you find your clothes lasting well?
You get full-text examples, with various possible replies from yes to no to maybe, and they add up to series of wonderful little soap operae: I find myself getting involved with these people. I'm very happy for Robert J. Smith, who passed his exam with flying colors. His friend Edward Green congratulates him, Robert writes Ed back to say thanks and mention how nervous he was, and Robert's mother is very proud.
There's something for everybody on every side of a transaction: How to solicit for a charity:
Dear Mrs. Mandell,
....As you are no doubt aware, the distress in this neighborhood is becoming very intense, and I have determined to make a special appeal to my parishioners in order to raise a fund to buy blankets and coal and food for the poorest of the poor. I should feel most thankful for any contribution, either of money or of the articles themselves. You can have no idea of the terrible state of poverty that I find on all hands. Many men are out of work and all this falls bitterly hard on the wives and children.
How to say yes:
Dear Mr. Fairchild,
....I enclose herewith a check for $5.00 which I earnestly hope may be of some help. It is indeed a distressing state of affairs. I hear on all hands the great need of the laboring people due to the lack of work and I am glad to do my bit.
How to beg off - man, this is a bit chilly:
Dear Mr. Fairchild,
....I have read your letter with great pain. It is indeed a terrible state of affairs, but it is my firm conviction that indiscriminate giving is the worst possible thing for the poor. The only real cure is to make certain of the continuity of employment. I would gladly subscribe to any scheme to bring that about. In the present condition of the labor market I feel sure that it would be useless to do anything that will merely temporarily alleviate and not definitely eradicate poverty.
...............Yours very truly
Now here's a situation where proper wording is vital: "Letter of proposal from a gentleman to a young lady he has met on only a few occasions."
(I worry about Paul and Mabel. Really, I do):
Dear Miss Lucey,
....I fear this letter will surprise you very much but I trust that the genuineness of my feelings will excuse me in your eyes. I first met you at Viola's dance in April and since then I have seen and talked to you on three separate occasions only. But the impression you first created in my mind was so powerful that I have thought of nothing else since then. Each time I have seen you since I have been more and more assured that you, and you alone, are able to give me that happiness which is every man's goal. I will not beat around the bush any more but will ask you straight out--will you marry me?
.....I implore you to think it over well. I cannot explain in writing how passionately I love you and with what joy I would dedicate my whole life to you.
....Although not rich I am comfortable situated and quite in a position to support a wife. I want to come in person and urge my suit and await therefore with profoundest anxiety an answer to this letter.
This sample answer is purportedly a "yes":
Dear Mr. Carlson,
....I hardly know how to answer your letter. It is quite true that we have met very seldom but I already feel as if I had known you for years. I will not say any more now but come around at eight o'clock tonight and you shall have your answer.
Here's how to nix the idea but leave some hope:
Dear Mr. Carlson,
....I need hardly mention that your letter came as a complete surprise to me. Al though I realize the genuineness of your sentiments and feel flattered that they should be directed toward me, I must tell you at once, both for your sake and mine, that all such ideas are quite out of the question. I do not believe in love at first sight and certainly would not trust my happiness to one whom I know so slightly. Forgive me if I appear to speak too plainly but I am convinced that it is the right thing to do. Such an acquaintance as I have with you has been a pleasure to me and I hope we may see more of one another. As for love it is really idle to talk about it.
....Please let us remain friends.
...........Yours always sincerely,
Then again, despite telling him how to propose, the author of Supreme Letter Writer is also fine with telling the lady how to write an "Angry reply":
....I have read your letter with the utmost astonishment. I consider it a gross impertinence. Please do not address me again either in public or by correspondence. You have greatly misjudged me if you consider I will tolerate such liberties. I would have handed your letter to my father to answer if it had not been for the trouble and annoyance it would have caused but if you address me in any way again I shall not hesitate to lay the matter before my parents.
And don't forget that you guys out there must make a lifetime commitment to a woman before you seek permission from her father to "pay her attentions" at all:
Dear Mr. Shaw,
....I am writing about a delicate matter because I feel it is the honorable course to pursue. It is this: I want your permission to pay attentions to your daughter Peggy. I have known your family now for over six months and from the very first I felt sure that Miss Shaw was the only girl I could ever love.
Favorable reply from dad:
Dear Mr. Bently,
....I am in receipt of your letter of the twenty-first, for which I thank you. I consider that you have behaved in an honourable and straightforward manner. Could you come round to my office in Ross Street at five o'clock tomorrow and talk this matter over. If, as I have no doubt will be the case, you can supply me with satisfactory information about your position and prospects, my wife and I shall have no objections to your paying suit to our daughter.
(Just wait everybody! 1929 is coming!)
And if you don't know how you feel about a man's proposal - have Mom tell you!
.......I told him that I could not give him any definite answer then and that I must think it over. I have known him only a short time, and yet I seem to know him so intimately. You will ask me, what are my feelings toward him. Well, that is just what I find it so hard to know. I think I care for him very much but he is so different from anyone else I have ever seen that I sometimes mistrust myself and imagine it may be only the effect of his delightful manner. Dearest mother, what answer should I give him? I resolved I would lay it all before you.
........With fond love
...........from your affectionate daughter
Mom actually seems to be OK with this, though she diplomatically throws in a caution:
My darling Sally,
....Take a few days to think it over but if you are certain that it will be for your happiness do not hesitate to accept him. Remember, dear little daughter, that marriage is either the greatest blessing or the greatest curse on earth.
.......Ever your devoted mother
Then again, if the kid has to ask, she shouldn't do it:
.....I am convinced that you will be doing the wisest thing if you refuse him. If he is still resolved to win you, this will not definitely retard him and with a further knowledge of one another you will understand your own hearts better.
............With deepest love
................Your devoted mother
Middle-aged people, of course, are not troubled by such passions. Or they aren't supposed to let on, even when proposing:
Dear Mrs. Ryder,
....I venture to address myself to you in the following manner because I know you will not misunderstand what I am going to say.
....You and I have both known the joys and sorrows of matrimony. We have both known many years of happiness and we have both lost the partners of our lives. And now in our middle age we are both living lonely lives, with nothing to look forward to but lonely old age. Is it not possible that this may be remedied?
.........Believe me, dear Mrs. Ryder,
.............Your sincere friend
Hey, if you can't get her interested by other means - depress her!
And in this sample acceptance, is there the subtle subtext of "OK, I'll darn your socks but you're not gonna get any"?
Dear Mr. Chenney,
....I will answer your letter quite frankly. I believe that it would be for our mutual happiness to marry. It would be absurd to pretend that we can look upon it with the same rapture as young people do but I sincerely think that we could be a help and comfort to one another.
........Yours very cordially,
Last but not least, the kind of letter I'm so very glad my boss can't send me, because I'm self-employed:
Dear Mr. Mason:
....Although I have spoken to you several times about your lax attention to your duties, I have been unable to notice any improvement in your conduct. I have therefore come to the conclusion that I must ask you to leave my service.
Well then, I guess I should get back to work...