Frankly, after reading the Johnsons' book on glass rods, I was expecting a better effort. I won't evict it from my reference shelf, but I didn't learn much if anything, and felt many of the chapters were "fluff"--more like press releases (in some cases, they were) than researched articles about the development of modern fly lines and the professional and corporate relationships that led us to today's selection of lines. Some companies that have been important to the sport were completely left out. Schwiebert's coverage of fly line development in "Trout" and the subsequent paperbound excerpted "Trout Tackle--One" was better, imo, although it suffers from having been written over three decades ago and thereby missing many of the greatest technical developments.
CC