She was a muse to many: Helleu painted her, James Lees-Milne worshipped her, Evelyn Waugh dedicated a book to her and Winston Churchill nicknamed her 'Dina-mite'. As the young wife of Bryan Guinness, heir to the Guinness brewing empire, she lived a gilded life until fascist leader Sir Oswald Mosley turned her head.

Unpublished letters, diaries and archives bring an unknown Diana to life, creating a portrait of a beautiful woman whose charm and personality enthralled all who met her, but the discourse of her life would ultimately act as a cautionary tale. This groundbreaking biography reveals the woman behind the myth.