I purchased it this evening and have been looking it over. From what I can tell at first glance it looks interesting and has a lot of nice detailed photographs of original doubles from Lewis Drake. It doesn't seem to have much in the way of photographs of the construction process, which is a shame. I think the E-book format should make it much easier to have more construction photos which should give it an advantage over traditional books. This book does have a lot of illustrations however.
I'd still go with Brockway's book on the subject as the standard, but this looks like it has its place too and certainly has some nice photos of original guns.
