The queen's secret : a novel of England's World War II queen / Karen Harper.

Enhanced descriptions from Syndetics:

If you love Jennifer Robson or The Crown you will love New York Times bestselling author Karen Harper's novel about Elizabeth, The Queen Mother.

1939. As the wife of the King George VI and the mother of the future queen, Elizabeth--"the queen mother"--shows a warm, smiling face to the world. But it's no surprise that Hitler himself calls her the "Most Dangerous Woman in Europe." For behind that soft voice and kindly demeanor is a will of steel.

Two years earlier, George was thrust onto the throne when his brother Edward abdicated, determined to marry his divorced, American mistress Mrs Simpson. Vowing to do whatever it takes to make her husband's reign a success, Elizabeth endears herself to the British people, and prevents the former king and his brazen bride from ever again setting foot in Buckingham Palace.

The Elizabeth holds many powerful cards, she's also hiding damaging secrets about her past and her provenance that could prove to be her undoing.

In this riveting novel of royal secrets and intrigue, Karen Harper lifts the veil on one of the world's most fascinating families, and how its "secret weapon" of a matriarch maneuvered her way through one of the most dangerous chapters of the century.