"I have a potato chip can filled with rejection slips for other things I've written, so I decided to published it myself," she said.
Dietrich had 500 copies printed. The book sells for $15 and can be bought at several area locations, including the Heritage Center in Chambersburg, Pa., Penn National Estates Clubhouse and Dru's Books 'N Things in Wayne Heights Mall in Waynesboro, Pa., and the Mont Alto fire hall.
She will sign books Sept. 24 at the Penn State Mont Alto Fall Festival.
According to the book, Mont Alto was called Funkstown, after John Funk, its founder, who settled in the area in 1817. A sentence in the book says there are conflicting reports that Samuel Funk founded the town proper in 1807. The name changed to Mont Alto around 1878.
Dietrich said she didn't know if the Funkstown in Franklin County had any connection to the town of the same name in Washington County.
Her house at 210 Main St., the former Union Hotel, shows up on the map of Funkstown in the front of the book.
On the cover is a photo of a sampler that was made by Catharine Knepper in 1842 from wool from sheep from a local farm, Dietrich said.
The town's early history stems from the iron furnace that gave the small community a "company town appearance," Dietrich said in her book.
The book's narrative and photos show slices of life through the 19th and 20th centuries.
At one time, three hotels catered to visitors to Mont Alto - the Union, the Clyde and Shank's. The thriving iron industry and the tuberculosis sanitarium in nearby South Mountain drew people to the area, she said.
Dietrich, a Baltimore native, ended up in Mont Alto because of her late husband, Daniel Dietrich. A U.S. Army colonel, he was stationed at Fort Ritchie. She became post historian at Fort Ritchie.
She has written many historical articles for area newspapers and other publications. She writes a monthly column on activities at Renfrew Museum and Park for a Waynesboro newspaper titled Something to Crow About.
Dietrich also speaks to area groups and organizations on historic topics.
Art is a primary interest. In her large home, she founded A Little Gallery of Mont Alto, which represented the works of artists and craftspeople in the Cumberland Valley.
The gallery held about 10 shows a year, she said. It closed in 1996.
"I was turning 70 and I wanted to paint and travel," she said. "I had the gallery for 20 years, and 20 seemed like a good round number to end on."
She is a student of noted area artist Lester Stone. Many of Dietrich's works hang throughout her home.