Winston Churchill helped save the world from the terror of Nazi Germany — and in return, the world’s bookstores have held an abundance of space on their shelves for Churchill.

The Churchill Sisters: The Extraordinary Lives of Winston and Clementine’s Daughters, by Rachel Trethewey. St. Martin's Press, 320 pp., $29.99.

Although he has only been dead for a little over 50 years, the amount of written material on Churchill rivals the global output of books on George Washington, Julius Caesar, Napoleon Bonaparte, and Abraham Lincoln. At the time of his death in 1965, there were already 36 published English-language books about the British World War II hero. In the past five years, the literary marketplace has seen 10 new books on Churchill. There are books on Churchill’s time as a war correspondent, Churchill’s interest in the Secret Service, Churchill and America, Churchill and Canada, Churchill and Islam, Churchill and liberalism, Churchill’s wife, Churchill’s money, Churchill’s military strategy, Churchill’s oratory, Churchill’s secretaries, Churchill’s sayings, Churchill’s paintings, and Churchill’s toiletries. (I made only one of these things up.) According to some estimates, there are nearly as many books about Churchill as there are on Alexander the Great and Jesus Christ.

It is safe to say the world does not need more books about Churchill. But what about books about his parents? Or his children? Here, perhaps, is where a genuinely original contribution to Churchill studies can still be made.

Following the lead of Erik Larson’s The Splendid and the Vile, which examines, in part, Churchill’s relationship with his daughter Mary and daughter-in-law Pamela, and Josh Ireland’s Churchill & Son, about Churchill’s relationship with his only son, Randolph, Rachel Trethewey, a longtime writer for British outlets such as the Daily Mail, Daily Express, and the Independent, had reason to believe that despite everything that has been written on Churchill, there had still been no adequate, full-scale treatment of the British Bulldog’s relationship with his daughters.

Her research in archival materials and the letters exchanged within the Churchill family revealed that the account of Churchill’s relationship with his daughters Diana, Sarah, Mary, and Marigold was one of the few remaining untold stories of his copiously documented life and legacy. So Trethewey set out to tell this untold story, and the result is her enjoyable and informative book The Churchill Sisters: The Extraordinary Lives of Winston and Clementine’s Daughters

Drawing on the memoirs of Mary and Sarah, biographies of Winston by acclaimed Churchill scholars Andrew Roberts and Martin Gilbert, archival materials from the Churchill archives in Cambridge, the letters Diana, Sarah, and Mary wrote to their parents, and interviews with Winston’s wife’s secretary, Trethewey paints a complex, sympathetic portrait of the entire Churchill family rather than just of Winston alone.

The Churchill Sisters, in fact, shows that even a solo portrait of Winston would be incomplete without considering the roles that his wife and daughters had in supporting his vigorous public life. Thanks to several other books, we already know about the essential role that Winston’s wife, Clementine, had in aiding him in his career. Trethewey shows that Winston’s daughters were nearly as important in allowing him to be as active in domestic and global politics as he needed to be. They were with him during his key World War II summits at Yalta, Tehran, and Potsdam (a story partially told last year in Catherine Grace Katz’s The Daughters of Yalta), where they made sure he was healthy enough and supported enough to continue to fight the Nazi menace. “In those crucial days,” Trethewey writes, “when the future of Britain hung in the balance, there were few people Winston could trust, and his wife and daughters were among the faithful few he knew would never let him down. … Staying strong for each other was no longer a purely family matter, it was of national importance.” In serving their father, the Churchill sisters served their country and the cause of freedom throughout the world.

However, The Churchill Sisters is not only a "great man of history" account of how “the greatest Englishman” was supported by the women in his life. Even more so than it is a book about Winston, it is a lively and moving work about Diana, Sarah, and Mary — Marigold tragically died too young to have a full life — who led whole, accomplished lives, at least as accomplished as the limitations of their gender would permit in their generation, and they deserve to have their full stories told as well.

Trethewey gives them, and us, this long-overdue gift in The Churchill Sisters (published originally in the United Kingdom under the title The Churchill Girls).

The Churchill girls, Trethewey writes, “were never just social butterflies” content to enjoy privileged lives of leisure because of their famous father. Instead, “from an early age they were motivated by a profound sense of duty.” Diana, nicknamed “Chatterbox” because of how much she liked to talk, suffered through a brief bad marriage before obtaining a divorce, still rare and stigmatized in those days, and took an active role in her father’s and brother Randolph’s political lives. She served as an air raid warden and as a welfare worker in the Women’s Royal Naval Service during the war. After battling depression and mental health problems, she found her calling in working for the Samaritans, a suicide prevention organization.

The charming, flirtatious Mary served in the soldiers’ canteen at Victoria Station and manned an anti-aircraft gun during the war. “The calm centre of the family,” she led a distinguished life in support of her father’s and husband’s political careers. The queen selected her to become a Knight of the Garter, the most senior chivalric order in Great Britain, in 2005. She also wrote an acclaimed bestselling biography of her mother. The ambitious, rebellious Sarah was the one Churchill daughter “who had inherited [her father’s] touch of genius.” She was also the Churchill daughter who was least keen on having children and a family. Instead, she eloped to America with her Austrian lover, pursuing an acting career.

Trethewey skillfully guides us through their trials and tribulations, adventures and romances, and tragedies and triumphs, presenting a complete picture of the lives of the Churchill sisters that also rounds out our picture of Winston, who here is revealed as not just a military leader and national hero but a devoted family man, a proud father who relished family life. He relied on it to support his work and help him “switch off from his work” when he needed an escape. By the end of The Churchill Sisters, we become convinced that Sir Winston’s daughters, no less than their father, deserve a space of their own on the world’s bookshelves.

Daniel Ross Goodman is a Washington Examiner contributing writer and a postdoctoral research scholar at the University of Salzburg.