This is an interesting book. It's somewhat a sequel to the Pat Garrett book, An Authentic Life of Billy, The Kid. It posits that Garrett shot a horse thief named Billy Barlow that night in 1881 and not Billy the Kid. This book jumps around telling what Billy did after the night he was supposedly "shot" and how he got his revenge.
It's a good story, but the author jumps around all over the place. It's told from several different points of view and several different moments in time simultaneously. It's a little disconcerting. I enjoyed the idea, but the book was a little tough to read.