“The beautiful owner of this book is dearer to me than my life - August your protector.” This one sentence was the key to a mystery involving some of the greatest and most infamous figures in European history, from Frederick the Great to Napoleon and Hitler - and solved by the author of this book.

Eve Haas is the daughter of a German Jewish family that took refuge in London after Hitler came to power. Following a terrifying air raid in the blitz, her father revealed the family secret - that her great-great grandmother Emilie was married to a Prussian prince. He then showed her the treasured leather-bound notebook inscribed to Emilie by the prince.

Her parents were reluctant to learn more, but later in life, when Eve was married and inherited the diary, she became obsessed with proving this birthright. The Secrets of the Notebook tells how she follows the clues, from experts on European royalty in London to archives in West Germany and then, under threat of being arrested as a spy by the Communist regime, to an archive in East Germany that had never before opened its doors to the West. What she unearths is a love story set against the upheaval of the Napoleonic wars and the anti-Semitism of the Prussian court - and a ruse that both protected Emilie’s daughter and probably condemned her granddaughter - Eve’s beloved grandmother, Anna - to death in the Nazi camps.

When first published in the UK, The Secrets of the Notebook was an Irish Times best seller. A movie based on the book is in production.