I don't actually own this one,
but so many of my students speak highly of The Fly Tying Bible
that I felt I had to
include it. This is actually half Technique, half Pattern book. It's a
British book, so the patterns are a bit different - and some a bit weird
to US tyers - but it gives you a good step-by-step of a good quantity of
useful patterns. Very good reviews by the people I know who have one.
Note that there are two versions, the ring bound and the spiral bound.

This is another of those books that will serve as a complete
reference for the beginning tyer. The early part of the book is filled
with sections on all the skills necessary to move forward - dubbing,
hackles, tailing, etc. Following this there are 50 different patterns,
each arranged on a two-page spread. The left page has a large photo of
the finished fly, and the right page has six different photos, with the
necessary steps listed underneath them. It lays open on the table so you
can just tie your way through any pattern.
I tended to think these books - everything from the Benchside
Reference on down - as a bit of a crutch, but I've come to change my
position. I think they're quite valuable, even when tying a familiar
pattern. It never hurts to have a quick review, or to perhaps pick up a
new technique you might have missed before. Good stuff. I think that
until the "Kindle" becomes ubiquitous, this will likely
represent the end of the line in fly tying instruction. I just never got
used to having the keyboard right next to the head cement.