For example, there's the story of beloved hymn-writer Fanny Crosby.
"I think most people knew that she was blind," he said of Crosby, who wrote the lyrics for "To God Be The Glory" and hundreds of other stately hymns.
"But she memorized huge chunks of scripture by the time she was 15, wasn't saved 'til she was 30, and didn't start writing hymns until age 40."
Brainard included three of Crosby's hymns in his new book, which features more than 60 songs grouped by theme into 10 categories.
All of the hymns are in the public domain (thus the title of the book), which means they are old enough to no longer have copyrights. The most recent hymn in the collection is Thomas Dorsey's, "Precious Lord, Take My Hand," written in the early 1930s.
"That song was Dr. Martin Luther King's favorite," Brainard noted. "It was performed at his memorial service in 1968."
The oldest song in the book? "A Mighty Fortress is Our God" which dates to the 16th Century.