Tom Bower's book, Revenge: The Battle Between Meghan, Harry and the Windsors, will be released on July 21.
According to reports, the biography of Meghan and Harry has "accounts from insiders who have never spoken before.
In media interviews, the writer said Meghan "crushed all those other people along the way" and added: "The victims are willing to talk and they have spoken."
The promotional material read: "Tom Bower, Britain's leading investigative biographer, unravels the tangled web surrounding Sussex and his relationship with the royal family. From courtroom drama to court politics, extensive research, expert sourcing and insider research." Using interviews from sources who have never spoken before, this book uncovers an astonishing tale of love, betrayal, mystery and vengeance."
Commenting on the book, royal expert Jesus Enrique Rojas said the Duke and Duchess of Sussex are intimidated by the biography.