My son and I spent a week fishing in the high sierra before buying this book. The fishing was good but sporadic. When I read this book, I was amazed at how well Van Loek was able to explain why we caught fish when we did and vice versa. The principals will be of value to spin fishermen as well as fly fishers. Add to that, the book is written in a colorful, simple, well thought out, engaging manner, and I have come to consider this one of my indespensible reference works for western trout fishing, the High Sierra and beyond.