Nigel Nicolson, who spent his life at the pinnacle of British intellectual and political society, died Sept. 23 at his grand country estate, Sissinghurst Castle in the English county of Kent. No cause of death was disclosed.

An author, soldier, publisher, politician and preserver of the British patrimony of grand houses and gardens, Mr. Nicolson, 87, practically defined the ideal of the aristocratic English gentleman.

Descended from baronets and lords, he grew up in the brilliant cultural milieu of Bloomsbury and from childhood was acquainted with the British and European elite. Yet in spite of his many achievements and his long life -- his memoirs, published in 1997, were called "Long Life" -- it was Mr. Nicolson's fate to live in the shadow of his even more illustrious, and unconventional, parents.

Mr. Nicolson chronicled their remarkable lives in the best-known of his books, "Portrait of a Marriage" (1973), in which he revealed that both of his parents freely indulged in homosexual affairs. Yet somehow they remained married and -- improbable as it may seem -- deeply devoted for 49 years.

His father, Sir Harold Nicolson, was a leading British diplomat, member of Parliament and historian. His mother, Vita Sackville-West, was an artist and writer best remembered for her tempestuous liaisons with women, most notably the novelist Virginia Woolf. They reached an amicable arrangement such that Woolf became a friend to the family, even accompanying young Nigel on butterfly hunts.

Mr. Nicolson was born in London on Jan. 19, 1917. With his father often away on official business and his mother otherwise engaged, he usually saw his parents only once a day, at 6 p.m. His mother, hardly a paragon of maternal virtue, blithely mixed remoteness with outright neglect.

"No one," Sackville-West wrote to her husband in 1928, when Mr. Nicolson was 11, "would want to have entire charge of two children for four months of the year."

As a result, young Nigel and his older brother, Benedict, grew up in a world of governesses and boarding schools. Mr. Nicolson attended Eton, the training ground for the British upper class, before graduating from Balliol College at Oxford University.

In 1932, his parents moved to Sissinghurst, an Elizabethan castle they restored from near ruin. With "Harold planning, Vita planting," in Mr. Nicolson's words, they returned the once-magnificent gardens to their former splendor. Mr. Nicolson would live at Sissinghurst the rest of his life, even after it was made part of the National Trust, a system for preserving Britain's stately houses. Its gardens, which attract 200,000 visitors a year, are perhaps the most renowned in England.

From 1939 to 1947, Mr. Nicolson was an officer in the British army and was dispatched to Palestine, Tunisia, Italy and Austria during World War II. To his lasting shame, he did nothing to prevent the transfer of some 70,000 Russian and Yugoslav dissidents to Communist authorities after the war, knowing they would face almost certain death. Four decades later, he would testify against a fellow British officer, a onetime friend, accused of war crimes in the incident.

In 1948, Mr. Nicolson helped found Weidenfeld and Nicolson, which became a prominent British publishing house that released the works of Saul Bellow and Lady Antonia Fraser, as well as the first British edition of Vladimir Nabokov's "Lolita."

After serving, with no great distinction, as a Conservative member of Parliament from 1952 to 1959, Mr. Nicolson turned his attention to his publishing company and to his own literary efforts. After his mother's death in 1962, he discovered a cache of her writings that he used to compose "Portrait of a Marriage," which was considered scandalous in its revelations of the easygoing sexual mores of the British culturati.

He was accused of betraying his parents and his class, yet the book's popularity helped propel Mr. Nicolson to a new career as a cultural historian, particularly of the bohemian world of his parents. He edited his father's diaries, as well as six volumes of "The Letters of Virginia Woolf." Both projects are considered among the finest personal writings in modern English literature. Mr. Nicolson also wrote biographies of military figures and writers, as well as books on history, travel, gardening and British manor houses.

In 1992, the same year his publishing company was sold, he published a volume of his parents' correspondence. He also began, at 75, to write popular columns in British papers and magazines. Modest and somewhat melancholy, these personal writings became the basis of his well-received memoir, "Long Life."

He wrote a book about Queen Elizabeth II in 2003, and this year he edited a collection of his father's letters. It was published three weeks before his death.

Unlike his parents, Mr. Nicolson led a rather proper life. His only marriage, to Philippa Tennyson d'Eyncourt, ended in divorce. Survivors include two daughters and a son, writer Adam Nicolson, with whom Mr. Nicolson collaborated on a 1987 travel book about the United States, "Two Roads to Dodge City."

If he didn't shed the memory of his celebrated parents, Mr. Nicolson certainly lived up to the epitaph he chose for himself: "It has not been a wasted life. It is studded with a few triumphs and many moments of delight."

Nigel Nicolson's "Portrait of a Marriage" disclosed his parents' affairs.