This is a book for those interested in the historical/technical aspect of glass. There's a fair amount of neutral, comprehensive history, but it's completely unafraid to delve (occasionally) into very technical molecular description and manufacturing processes. It's successful at addressing a range of audiences, in that respect. (Just ignore the bits you can't or don't want to understand.) This would be an appropriate book for someone who had absorbed a few other glass books, say on the history of glassware, perhaps collecting, and perhaps camera lenses. The book could easily have been three times as long, the authorship is excellent and authoritative.