It's even got an ISBN number and listed in book catalogs, but it's never been published.
It's "for sale" on several sites including Amazon and Walmart but it always says not available or out of stock
(-never was in stock).
https://www.worldcat.org/title/truth-massacred-the-battle-at-fort-pillow-tennessee-april-12-1864/oclc/922836106#borrow