is this in the Book? what I am interested in is the last statement!
As the only child of Louis XVI and Marie Antoinette to survive the French Revolution, Marie-Thérèse-Charlotte de Bourbon occupied an extraordinary place in history. Surprisingly, not much has been written about her; she is dismissed by her mother’s many biographers as, variously, “unbearably haughty,” “sulky,” “ill-tempered” and even (from the mordant Stefan Zweig) “mentally inert.” This was a girl who, upon being asked how she would feel if Marie Antoinette were to die, replied, “I would be very glad because I could do as I pleased.
I was sort of hoping She had referred to her sources when She made her comments. But in her other book titled Mistress of the Elgin Marbles I note that in the Acknowledgement Section Nagel refers to the Family letting her have Mary's Diary and pictures. as below
http://books.google.com/books?hl=en&id=9UG2THvlxpkC&dq=susan+Nagel+biographyl&printsec=frontcover&source=web&ots=8S_MDMMseG&sig=8u2uHfuQXN7E1RnioFqMtOpUYno&sa=X&oi=book_result&resnum=1&ct=result#PPR10,M1In chronicling her subject’s rarefied, peripatetic existence, mostly spent in exile in foreign kingdoms, Nagel dismisses distasteful rumors — that Marie-Thérèse had been poisoned and raped in prison; that she kept a lover after her marriage. One wishes Nagel had done the same with the long-held conspiracy theory that on leaving France, Marie-Thérèse switched places with a half sister and lived out her life in seclusion in Germany. Although Nagel seems to discount the idea of “the Dark Countess” in her preface, and, using handwriting samples, forcefully discredits it in her afterword, she intersperses the book with melodramatic passages about this mysterious figure. Because we never believe the story might be true, Marie-Thérèse’s doppelgänger functions less as a red herring than as a dead one.
Review from the New York Times the above quote came from:
http://www.nytimes.com/2008/04/20/books/review/Steiker-t.html?n=Top/Reference/Times%20Topics/People/N/Napoleon%20ISusan Nagel is the author of a critically acclaimed book on the novels of Jean Giraudoux. She has written for the stage, the screen, scholarly journals, the Gannett newspaper chain, and Town & Country. A professor in the humanities department of Marymount Manhattan College, she lives in New York City.