Now this is of course a public book, but Harrison obviously worked through a lot of rituals, so it would be interesting if he'd make a (less public) book with more comparisons. He only does that here and there in the current book. There are also images of handwriting of John Yarker and such, but usually fairly small.
I think the book is most fun for British Masons, since the author mentions a lot of (almost) lost British Rites that arose in the time before and just after the union when rituals weren't printed yet.
Like I said, it's an alright read, but don't expect more than anecdotes and 'petits histoires'.