This description of the book from Amazon.com summarizes it well.
Lady Almina and the Real Downton Abbey tells the story behind Highclere Castle, the real-life inspiration for the hit PBS show Downton Abbey, and the life of one of its most famous inhabitants, Lady Almina, the 5th Countess of Carnarvon and the basis of the fictional character Lady Cora Crawley. Drawing on a rich store of materials from the archives of Highclere Castle, including diaries, letters, and photographs, the current Lady Carnarvon has written a transporting story of this fabled home on the brink of war.It’s filled with photographs of the Castle and various family members to help put faces to the names. I recommend it to those who enjoy history, especially of the Edwardian and World War I period in England. A special bonus since I love Egyptian archeology, Almina's husband was the Lord Canarvan who funded the expedition that located King Tut's tomb. There are chapters about this event as well. So interesting!
Much like her Masterpiece Classic counterpart, Lady Almina was the daughter of a wealthy industrialist, Alfred de Rothschild, who married his daughter off at a young age, her dowry serving as the crucial link in the effort to preserve the Earl of Carnarvon's ancestral home. Throwing open the doors of Highclere Castle to tend to the wounded of World War I, Lady Almina distinguished herself as a brave and remarkable woman.
This rich tale contrasts the splendor of Edwardian life in a great house against the backdrop of the First World War and offers an inspiring and revealing picture of the woman at the center of the history of Highclere Castle.