The book has been out since 2006. It is a valuable book re what to use, when to use and how to use. Particularly informative were the segments: ‘behavorial drift’ and determining the most likely nymphs drifting in a body of water (behavorial & emergent drifts). The book is full of excellent information. Any work by Hafele is excellent for the fly fisher/fly tyer regardless of level of expertise. Dry fly purists need not apply.