tremendous amount of knowledge on fly fishing from this man. Too bad his editor is so bad with all the misspellings and wrong words. Have yet to definitively try out his casting technique...
This one's fine. It's a not-too-detailed look at how to improve your fly casting. It's mostly straightforward, but it's very brief, with drawings that are usually clear and useful. If you wanted to learn to (or improve) your fly casting, you'd want to go somewhere else.
Kreh teaches a different style of casting than I've seen elsewhere. I saw him demonstrate it at an outdoor show in Denver (where I couldn't hear him that well), so the sections on basic casting in this book made sense to me. However, I'm not sure how clear they'd be to someone who hadn't seen it in practice, especially since it goes against much of what we're typically taught.
There's not enough "why" in this book -- even if you learn the technique, I think it's always good to have a fuller understanding of why something works.