These prologues were memories, but not used as flashbacks. The Josiah novels are linear. Once they start in chapter one, they move forward, and don't change POV (point of view) and I don't shift in time--flashbacks occur as memories or thoughts. I was as strict with this third person POV as I would have been if I had written these six novels in first person.
The prologues served the story in way that would have been impossible inside the text with the rules I established for myself. They also allowed me to use characters from previous books in the newer books, creating a consistency that wouldn't have existed otherwise, at least not as powerfully.
I had a very distinct purpose for each of the prologues, and how it overshadowed the novel. In the first book, The Rattlesnake Season, the prologue drops the reader into the one of the most serious emotional crises that Josiah would ever experience: the death of his wife, and the birth of his son at the same time.
In the last book of the series, The Gila Wars, the prologue opens in the final days of innocence for Josiah--he learns from Charlie Langdon, his nemesis in book 1, that the railroad is not coming through town, essentially putting the final nail in the coffin of the town's existence. As marshal of this town, Josiah knows the town will die, and that change is coming. Charlie goes off on his outlaw rampage, and the theme of change is set for the reader. I never wrote this scene in book 1 because the book starts two years after the death of his wife, and even longer than that after this incident. It was something that I felt the readers of the series would get right away.
This might be an unconventional use of prologues, but I've also thought it made the series a little different. Prologues can be useful if they serve the story in a unique way.
So when someone says that a writer should absolutely not use prologues, question that, and how it applies to the story as whole. For me, I considered the story arc of the entire series, not just one book.
The Gila Wars, the final Josiah Wolfe, Texas Ranger novel releases May 07, 2013.