Sylvia : queen of the headhunters : an eccentric Englishwoman and her lost kingdom / Philip Eade.

Enhanced descriptions from Syndetics:

THE EXTRAORDINARY TALE OF SYLVIA BROOKE, THE LAST WHITE RULER OF THE JUNGLE KINGDOM OF BORNEO

Sylvia Brooke was one of the more exotic and outrageous figures of the twentieth century. Otherwise known as the Ranee of Sarawak, she was the wife of Sir Vyner Brooke, the last White Rajah, whose family had ruled the jungle kingdom of Sarawak on Borneo for three generations. They had their own flag, revenue, postage stamps, and money, as well as the power of life and death over their subjects--Malays, Chinese, and headhunting Dyak tribesmen. The regime of the White Rajahs was long romanticized, but by the 1930s, their power and prestige were crumbling. At the center of Sarawak's decadence was Sylvia, author of eleven books, mother to three daughters, an extravagantly dressed socialite whose behavior often offended and usually defied social convention. Sylvia did her best to manipulate the line of succession in favor of her daughters, but by 1946, Japan had invaded Sarawak, sending Sylvia and her husband into exile, ending one of the more unusual chapters of British colonial rule.

Philip Eade's Sylvia, Queen of the Headhunters is a fascinating look at the wild and debauched world of a woman desperate to maintain the last remains of power in an exotic and dying kingdom.