The author of Ghosts in the Garden recently wrote down a list of reasons people might want to read her first novel. They range from the simple—”This is a mystery novel”—to the frank—”I have tried to make my sex chapters loving and beautiful instead of ugly and explicit”— but she saves the book’s best selling point for last. “Marylanders would be interested in reading it because they are Marylanders, and many people still remember Millard, my daughter Eleanor, Joe, and me.”

And even locals who aren’t on a first-name basis with Eleanor Davies Tydings Ditzen might recognize at least one of the surnames stacked up in her byline.

Ditzen’s second husband, Millard Tydings, served from 1927 to 1951 as a U.S. senator from Maryland. Her son, Joseph Davies Tydings, held the same office from 1965 to 1971. Her third husband, the Rev. Lowell Ditzen, served as the director of the National Presbyterian Center in Tenleytown.

And her father, Joseph Edward Davies, was a diplomat and political adviser to three U.S. presidents. “My father got [Woodrow] Wilson elected president,” says Ditzen. “All the Wilson women just adored him.” Davies remains one of only a handful of politicos entombed in the National Cathedral.

Ditzen, now 99 years old, arrived in the District in 1912 when her family relocated from Madison, Wis., to a house on Connecticut Avenue NW. Nine decades later, she lives on the seventh floor of the Shoreham West building on Calvert Street, in an apartment decorated with portraits of her former husbands, a set of Russian landscapes that her father collected while serving as ambassador to the Soviet Union in the ’30s, and various letters, many penned on White House stationery. (“Dear Eleanor DTD,” wrote Hillary Rodham Clinton. “I always enjoy our times together and hope we will have many more occasions to trade stories and laughs.”)

In 1997, Ditzen chronicled her Washington insider’s life in My Golden Spoon: Memoirs of a Capital Lady. The book brims with vignettes about dining with various presidents, but there isn’t much about her novelist ambitions. Then again, those ambitions came later in life.

“I had already written my life’s story,” says Ditzen about her decision to write Ghosts. “So I thought I would try writing some fiction.”

Ditzen says she banged out Ghosts in the Garden over a span of about three months. She didn’t do much research for the book, which is loaded with historical tidbits about the Maryland lands near the Susquehanna River. Instead, she relied on her own experiences. “I didn’t have to study the history,” she says. “Millard taught me everything there is to know about the area.”

Much of the novel is set in the early 1900s, at a country estate called Oakley Manor on the west shore of the Chesapeake Bay. Ditzen based Oakley Manor on her memories of Oakington—her family’s former estate, which included a 40-room house and 600 acres of property near Havre de Grace. Today, her name has become a part of that region’s geography: Not far from the novel’s setting, the Millard E. Tydings Memorial Bridge straddles the Susquehanna River.

For her next novel, though, the Washington doyenne is looking beyond the Beltway and outside Maryland to a galaxy far far away for inspiration. “I am working on a book of science fiction,” says Ditzen. “I plan on calling it The Man from Andromeda.” —Felix Gillette