Stackpole Books, it's 256 pages and available in hardback and ebook formats. The author, Rick Takahashi, is well known in the fly fishing world and has over 60 years of experience creating and tying flies (and fishing).
My background with fly tying is fairly unusual, I think. I've never met a fibrecraft I didn't enjoy, and when I was teaching a class in tatting a couple decades ago, there was a man in my class who was also an avid fly tier. We traded instruction and though I'm not sure if he's still tatting, I am still tying the occasional fly. I'm not an avid fisherman and I don't really even like to eat fish (blasphemy, I know). I have heard over and over from other fly tiers that it's meditative and I've found it to be true. It can be very relaxing to spend time tying flies and it's always a bonus to wind up with something functional at the end.
This book is laid out very logically. It does follow on from Mr. Takahashi's earlier books with in-depth step by step tutorials for many of the flies he developed earlier. Each chapter starts with a generic body form and provides several alternatives for producing specific insects/nymphs. The ties are progressively more detailed as they go on.
There are 12 chapters dealing with different flies for different applications (and a good solid explanation of where and when to use each). These 12 chapters are followed by 2 chapters with different techniques for different environments. The book ends with a functional index. There are probably a couple hundred flies altogether including variations of each main archetype (That's an estimate, I didn't count them).
The tutorials are well photographed and the book is enhanced by the addition of really beautiful photos out in the field with a lot of gorgeous healthy trophy fish and action shots.
One thing I really liked was that, although the author does write which specific supplies he uses, there is no 'shilling' in this book and he isn't trying to push only his own products. He says what he personally uses and leaves it at that.
Beautiful book, well photographed, well written, very useful. Would make a lovely gift for an angler or fly tying hobbyist. Don't discount the possibility that someone in your life who knits, sews, tats, or does other fibrecrafts would also enjoy a try at tying flies.
Disclosure: I received an ARC at no cost from the author/publisher for review purposes.