This pair of books is a lovely final chapter in the incomparable legacy of Ernest Schwiebert. Although he died before finishing this master work, his very capable son, Erik, finished the project with the help of a who's who of entomolgists, biologists and many others in the scientific community. It is a serious angling work, "...intended, after all, for an audience of serious anglers." And, it should be noted that this abundance of information is provided, couched comfortably in the author's mellifluous tales and his resonant, implacable voice.
These books should be on any serious anglers shelf, period. And, if you are not serious, then these books might make you so.

Nymphs Volume II is a great addition to a fly fisherman's library. Highly detailed descriptions of various aquatic insects, with fly recipies for each one. Great color plates of drawings of the actual insects. This an excellent book as both a reference as well as an enjoyable read. Well worth the price - Also check out Nymphs volume I (Mayflies) I was so impressed with Volume II, I purchased Volume I.