Are You Shrieking? : LOVE FROM NANCY: The Letters of Nancy Mitford, <i> Edited by Charlotte Mosley (Houghton Mifflin: $35; 527 pp.)</i>

“I can’t do more than skate over surfaces, for one thing I am rather insensitive as you know, and for another not very clever.” So why should anyone be interested in the letters of the English writer Nancy Mitford? First, because they are very funny and sometimes very sad. She writes with wit, energy and an uninhibited malice. Entirely without self-pity, she makes jokes when her heart is breaking.

The second reason for reading them is that they give access to an exclusive milieu, and an exclusive mentality. We tend to use the term middle class to mean elitist and privileged. In these letters, middle class means dowdy and common. The Mitfords are upper class. The difference is, or was, almost one of caste. Nancy’s accent was so exaggeratedly cut-glass that she was unable to give radio talks; the listeners became enraged. If the shameless Mitford snobbery makes you want to throw up, approach the letters initially in a spirit of social anthropology. You will rapidly be seduced into reading for pleasure.

Nancy only died in 1973, yet her world could not be further removed from the modern experience, whether British or American, if she had lived in the 18th Century. Louis XV, she said, was not so different in outlook from her own father. Nancy referred everything and everyone to her own circle. Her four historical biographies all read, according to one critic, like “further adventures of the Mitford family.” Her first love was Hamish Erskine, a rakish homosexual younger than herself, and a character in her novel “Christmas Pudding” was Hamish “to the life,” as she confessed in a letter. No nonsense here about separating the work from the life: “I’m writing a book about us when we were little,” she wrote to her sister Jessica about her novel “The Pursuit of Love” (1945), which sold 200,000 copies in the first year.

The Mitford family have become mythical to posterity, as they were to themselves. Born in 1904, Nancy Mitford was the eldest of the seven children of an eccentric English peer and his almost equally eccentric wife. The only boy was killed in World War II. The six girls, all good-looking, ran to extremes. Diana married the leader of the British Fascists, Sir Oswald Mosley, and shared his views. Unity became infatuated with Hitler and attempted suicide in Germany when hostilities broke out. Jessica went the other way and became a member of the Communist party. Deborah married into the purple and is the Duchess of Devonshire. Pamela, the least exotic, married the distinguished physicist Derek Jackson. All but Unity and Nancy are still living, and nearly all of them have written books, as did their friends. “How nice and clever we all are,” Nancy wrote to the poet John Betjeman, with a characteristic mixture of pleasure and self-mockery.

Nancy candidly confessed her literary limitations in letters to her great friend Evelyn Waugh: “Not enough intellect, no education and no technique.” Waugh wrote in a review of her novel “The Blessing” that she had achieved “a patchy light culture and a way of writing so light and personal that it can almost be called a ‘style.’ ” The same is true of her fluent, gossipy, teasing, outrageous letters. Over 8,000 have survived. This volume contains around 500, addressed to more than a hundred different people. She fully expected them to be published one day, and began annotating her correspondence in her later years. “Won’t the editor of my letters have a jolly time, I often think,” she wrote to her sister Diana.

The editor of Nancy’s correspondence, Charlotte Mosley, is Nancy’s nephew’s wife. It was a sound plan to keep it in the family. Footnotes are needed to virtually every letter, explaining tribal jokes, nursery slang, coded abbreviations and the identities of the people referred to, usually by nicknames. Nor do Nancy’s friends and family have just one nickname each; Deborah, for instance is variously Debo, Miss, Nine, Henderson or Hen. Diana is Bodley, Honks or Nard. You need to keep your wits about you.

There are probably not enough footnotes for American readers, nor for younger British ones, for whom a phrase like “bronco not bromo” must be hermetic. It has to do with varieties of toilet paper--not a term that Nancy herself would have used. Toilet is grossly non-U, according to the half-joking analysis Nancy made of upper-class usage, which the general public fell upon with fascinated seriousness. In Nancy’s circles, even toilet rolls were out of order, and soft or colored paper beyond all horror. Only interleaved sheets of old-fashioned prickly paper were socially acceptable. There is quite a bit of shrieking correspondence about this, as about other manifestations of the Modern Age. (“What are jeans?”) Like the complaints about servants and the unwarranted familiarity of waiters, it is all designed to amuse, but the nostalgia for an undemocratic lost world is genuine enough.

Politically, Nancy veered between her sisters’ extremes, ending up vaguely left of center. Deeply conservative, she would be called, in today’s Britain, a “champagne socialist.” She denounced Diana to the authorities as a dangerous person, which led to Diana’s imprisonment during the war; yet Diana was perhaps her favorite sister. Nancy’s view was that “There isn’t a pin to put between Nazis and Bolshies--if one is a Jew one prefers one and if an aristocrat the other. Fiends.”

Nancy’s own “cause” was love--eternal, unrequited love for Gaston Palewski, a short, squat French colonel who was head of General de Gaulle’s cabinet in exile during the war. After the war, she went to live in Paris to continue her affair with Palewski, and stayed there for the rest of her life. Elegant and sociable, she embraced French culture, French fashions and French high society, enjoying smart parties in elegant Parisian houses (“such objets de musee on every hand, such food and such Dior dresses on such pretty silly ladies”).

Palewski was fond of her, but not in love and not faithful. He was terrified of scandal. They never traveled together, nor spent a whole night together. Her only hold over him was that she amused him--so she had always to be witty and entertaining, concealing her pain. The saddest part of the story is toward the end, when she was diagnosed as having cancer in the same week that he told her he was finally getting married, and not to her. Nancy chose to see the marriage, and Palewski’s wife, as nugatory: “She’s a sort of dead person, an anti-person, always very amiable but with no apparent reason for being on this earth.”

Nancy lived, in increasingly physical pain, for another five years. Her last letter, written half in French and half in English, was to Palewski. There is a final footnote: “Palewski was the last person to see her alive; he visited her in the morning and although she appeared to be unconscious, she smiled as he took her hand.” Nancy in her letters constantly punctuates her jokey anecdotes with the question, “Are you shrieking?” meaning “Are you laughing?” By the end of this volume, paradoxically, the reader is close to tears.