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The
Fly Tier's Benchside Reference 
The Fly Tier's Benchside Reference
by Ted Leeson, Jim Schollmeyer
Every dressing technique I've ever heard of is here!
This is not a book that provides patterns and technique; this is a book of techniques that may be applied to patterns.
George R. O'Connor, December 11, 1998
Advanced
Fly Tying: The Proven Methods... 
Advanced Fly Tying
by A. K. Best, et al
AK Best is acknowledged as one of the best fly tyers of the day.
Dyeing
and Bleaching Natural Fly-Tying... 
Dyeing and Bleaching Natural Fly-Tying Materials
by A. K. Best, John Gierach (Illustrator)
The book I used when I wanted to learn how to dye was by AK Best. Worth every penny at this discounted price
Well-known to readers of John Gierach as that author's occasional sidekick on western trout streams, A.K. Best wades into the deep waters of the angling library himself with an authoritative and instructional look at fly-tying. Best details the tying methods for his own popular creations as well as old standards, with plenty of photos of both naturals and their imitations. Also inlcuded is an introduction by Gierach.
Carrie
Stevens: Maker of Rangeley 
American Streamer patterns I guess are to the US what Spiders are to yorkshire. I think they are beautiful and I shall be putting some effort into mastering the techniques.
Streamer
Fly Tying and Fishing 
Col Bates book on streamers is what I have at the side of my bed at the moment. All the patterns with the techniques of how to tie and fish. An American classic on those beautiful wet flies
Fly
Pattern Encyclopedia: Federation of...

Fly Pattern Encyclopedia: Federation of Fly Fishers
by Al Beatty (Editor), et al
Plenty of patterns from Al Beatty and friends
Trout Flies
by Gary Lafontaine, et al
LaFontaine's landmark book Caddisflies set the standard for taking a scientific approach to the sport of catching trout on a fly. In Trout Flies: Proven Patterns, he combines observation with a deep understanding of entomology to examine the art of fly tying. This large, attractive volume boasts color plates, step-by-step diagrams, and the author's lively discussion of patterns that work--and why they succeed.
Hailed as a classic almost as soon as it came out in the early 1980s, this combination of entomology and fly-fishing instruction puts a small insect--the caddis fly--under the microscope to help anglers get big results on the water. Patterns that work on the Wharfe Ribble and Aire in Yorkshire straight from the USA
The
Fly-Tying Bible: 100 Deadly Trout...
The Fly-Tying Bible
by Peter Gathercole