A.K.A. the fiber-lover’s bible. I’m pretty much obsessed with this book by Deborah Robson and Carol Ekarius. Super-interesting information about more than 200 breeds of sheep, goats, and other fiber-producing critters (musk ox! camelids!). It has lots of technical info about staple length, fiber diameter, etc., useful for spinners and dyers. (The interesting historical information about alpacas and llamas in my Menagerie Hill Ranch post came from F&FS.)
And the pictures are fantastic. My personal favorite is the Leicester Longwool photo (page 92). It is 50% high-fashion, 50% rennaissance oil painting, 100% beautiful, curly fleeced sheep. Awesome.