Sonia Purnell has won the 2020 Plutarch Award for Best Biography for her book A Woman of No Importance: The Untold Story of the American Spy Who Helped Win World War II.

The award, which comes with a $1,000 honorarium, is given each year by the Biographers International Organization (BIO).

Purnell’s book tells the story of Virginia Hall, an American woman who worked with two spy agencies, Special Operations Executive and the American Office of Strategic Services, to prop up the French Resistance during World War II. A reviewer for Kirkus called the book “remarkable” and “significant.”

“Virginia Hall was a hero in the true sense of the word, and I am thrilled beyond words to receive the Plutarch Award as a tribute to her legacy,” Purnell said in a statement. “I see myself as the lucky one who got to tell her story. She didn’t always make it easy, but we got there in the end! Thank you for this incredible honor, which is a treasure to me.”

Finalists for the award included George Packer for Our Man: Richard Holbrooke and the End of the American Century and Jacquelyn Dowd Hall for Sisters and Rebels: A Struggle for the Soul of America.

The Plutarch was first awarded in 2013, to Robert A. Caro’s The Passage of Power. Past winners have included Ruth Franklin for Shirley Jackson: A Rather Haunted Life, and David W. Blight for Frederick Douglass: Prophet of Freedom.

Michael Schaub is a Texas-based journalist and regular contributor to NPR.