Trout can be very difficult to see in the water. One of the most useful parts of this book teaches us how to find & see trout in their environment. To me, this was very helpful information. Trout are very well hidden & easily frightened, so finding & seeing them without scaring them away is a difficult task. I've always believed that I scare more trout than I ever see or catch in a day on the stream. But, there are certain things to look for, certain flaws in the trout's camouflage that anglers can exploit to find the trout. This book goes into great detail about these techniques. Finding & seeing trout is a skill all unto itself & takes practice. This book will help you improve those skills a lot.
The other part of the book discusses how trout see. In this part, the authors take us into the world of the trout & we get to understand what it is like for the trout living under water. This is especially helpful, as the book teaches us just what a trout sees as our flies enter into their field of vision. We can't fool very smart trout consistently if we don't know what the trout is seeing & how. This part of the book, too, is especially helpful & will be eye opening to many anglers.
This book wasn't written in a season. The authors worked for years, doing exhaustive research both on the stream in in books. The result is this book which really uncovers all the layers of the mystery to what trout actually see & how they disguise themselves from predators. It's a well written, concise book filled with extremely valuable information to any trout angler.
Don't be put off that this book is over 30 years old. Trout still act the same as they did back then. Don't think the book won't help you because the authors are British, living & fishing across the ocean. The natural behavior of trout & their physical vision is the same anywhere trout live. You don't need this book to catch a lot of trout, but reading it & doing exactly what the authors say will most certainly help you to catch more trout, more often, & especially those very difficult experienced trout who aren't easily fooled by us anglers.