I have the book. Could it have been better? Yes. Does it engage in a lot of speculation? In places, yes. Look back at the works from Carder and Vorisek. They also tossed around speculation. Thats what you do when no records remain. I have read through my copy of Niles' work three times. It was written by an enthusiast that did his best from his home office to convey his study. Several of the manufacturers get little coverage, but what Nick, I believe, really clarifies are the guns manufacturered by the Crescent Fire Arms Co. and its' history. There are at least 12 variations of the Crescent hammer sidelocks, and the book separates them all chronologically, by design features, and a quite close estimate (read that speculation) of serial number by variant. These were the guns sold to the masses. And Nick, may not be the author we were expecting, but he made the attempt. I think it was a good one.
John
Your characterization is certainly more generous and fair than mine. You're right, the author deserves a lot of credit for the work he's done. I just wish he had hired an editor. (In the interest of full disclosure, I was a publication editor for 20+ years so I'm probably more offended by the stylistic things than most readers).