Steelhead books I recommend are John Shewey "Steelhead Flies" and H. Kent Helvie "Steelhead fly tying guide". These 2 are awesome for the diffrent wing techniques, spey, dee, shrimp style flies. If you also want good reference for patterns with a bit more history, the Chris Mann books are great for this. The benchside books are great and should be in every tyers library IMHO. Schewey's books would be my top pick though.