It wasn’t popular to talk about slavery in 1927. But Nellie Arnold Plummer took out a $1,000 mortgage to tell her family’s story.

The Hyattsville-area schoolteacher was well into her 60s when she self-published “Out of the Depths, or, The Triumph of the Cross,” using her father’s diary and family letters as source material, a half-century before Alex Haley’s “Roots.”

It was a story worth telling. Her father, Adam Francis Plummer, was a former slave at the Riversdale plantation who built his own house, a 10-acre property he called Mount Rose that was  just over the tracks from the present-day location of Busboys and Poets. The family prospered, with Nellie becoming the first woman to attend a Washington seminary while her twin brother became a well-known pharmacist.

(The house at Mount Rose was at Ingraham Street and 46th Avenue in Edmonston, though the official historical marker is down on Decatur Street instead.)

In recent years, “Out of the Depths” has seen a resurgence of interest.

In 1997, the book was reprinted as part of a series on African-American women authors overseen by Henry Louis Gates Jr. And in 2003, thanks to the work of University Park historian Margaret Law Callcott, Adam Francis Plummer’s original journal was donated to the Anacostia Museum run by the Smithsonian, where it is being preserved and studied.

For everyday readers, it’s a bit harder. Even new copies of “Out of the Depths” are generally pretty pricey. Though the book may no longer be under copyright, it is not available on Google Books or as an e-book.