IN 1937 THE DANISH writer Karen Blixen, who wrote under the name of Isak Dinesen, published Out of Africa, an elegiac account of her life on a coffee farm in Kenya. It has become a classic memoir, eloquent of her own vivid personality and of her understanding of the black people -- Kikuyu, Masai, Somali -- among whom she lived, and of her love for the wild life of the Ngong Hills. It is also a sad book, because the farm failed and in 1931 she had been forced to abandon the place that had become "a kind of child for me." Letters from Africa is a selection of her correspondence with her family in Denmark during her years there: in effect the private story behind Blixen's great memoir, it reveals how much more she suffered than she revealed in One of Africa.

Born in 1885, in 1914 she married a compatriot, Baron Bror Blixen, and with money put up by her family they established themselves in what was then British East Africa -- a pioneering territory, being newly exploited by speculators, idealists and misfits from northern Europe. Within a year she discovered her husband had given her syphilis. It was brought under control, but for the rest of her life she suffered from severe pain, infections, debility, and a tubercular spine as a result. Within a few more years Bror Blixen also proved himself incapable, because of his unreliability over money, of running the farm. Karen Blixen's family put her in sole charge, and the couple was divorced.

She ran the estate with a feudal paternalism -- or maternalism -- that might now be unacceptable, but then was not. The close community of workers, servants and squatters at Ngong was her own creation, and "her" natives were "the really great passion of my life." Her other passion was for an English farmer and safari hunter, Denys Finch Hatton, a younger son of the earl of Winchilsea. He came and sent at the farm as he chose; she loved him, and longed to bear his child. She wrote to her brother Thomas: "I believe that for all time and eternity I am bound to Denys, to love the ground he walks upon, to be happy beyond words when he is here, and to suffer worse than death many times when he leaves."

For as long as possible she had kept from her family the true reason for her chronic ill-health; and she never did tell them that her happy relationship with Finch Hatton grew less happy as he strove to keep some distance between them. It was perhaps a mercy for her that he crashed and died in his private plane in 1931; she buried him in the Ngong Hills and kept her dream. But that year saw a double tragedy: not only the death of Denys, but of her farm. tHer family could subsidize its losses no longer, and the "Karen Coffee Co." was wound up. She made on suicide attempt (her own father had committed suicide) and her letters home at this time are desperate and broken-hearted, but she survived to live on, at her family home in Denmark, to the age of 77.

These letters are valuable in two important ways. They will direct readers back to her unforgettable Out of Africa, to which they constitute an instructive and painful subtext. They are also, as the editor writes in his introduction, "messages of hope" -- particularly for women, but for all lonely freethinkers. In her later years on the farm, Karen Blixen wrote long, closely argued letters to her family about her experiences and opinions, her conclusions being all the more remarkable in that they were reached quite alone, "gathered together and clarified for myself," as she says. rAmong her preoccupations were women's emancipation, sexual morality, marriage, birth control, national characteristics, social values, and the affectionate claustrophobia of family life.

At Ngong she was no ascetic or recluse; she was vain abuot her appearance, enjoyed good food and good clothes and any excitement. (Once she entertained the prince of Wales -- the future Edward VIII -- at Ngong.) She called herself "God's chosen snob" -- she likes the aristocracy and the intelligentsia, and she loved the black people. What she hated were middle-class attitudes and middle-class family morality. Some of her best letters about this were to her clever, spinster Aunt Bess, to whom she wrote that "there is so much in life to love, so much to live for, that to me there is something blasphemous about this monopoly of love and cooperation between human beings by marriage and family life."

Some of ehr arguments were perhaps making a virtue bout of necessity; her husband had let her donw, and Finch Hatton would not commit himself. Her experience did not embitter her at all, but ti wiped her clean of sentimentality and sharpened her wits -- on marriage, for example, again to Aunt Bess: "I think that married happiness very often consists in one's purchasing the continuous, -- and unreasonable, - approbation and admiration of the other with a continuous, - and unreasonable, -- admiration and approbation of him; in the end neither partner can manage without this, but what has been achieved by it?"

There are funnier and more trenchant passages too long to quote here, including a brilliantly acute analysis of the traditional relation between the sexes and of the idea of "womanliness," written to her sister Ellen. It is her will and complete lack of self-pity that make Karen Blixen so sympathic and save her from the alienating intensity of other solitary searchers such as, for example, Simone Weil. She quotes a definition of true pity as "loving one's destiny unconditionally." To be able to do this without losing her resilience was part of Karen Blixen's achievement.