I read Vince Marinaro's "Modern Dry Fly Code" for the first time this year, and then read it three more times. I think it's the best book ever written about the kind of spring creek fishing I do. His observations about terrestrials and minutiae are dead on. In my own case, I had figured out the terrestrial part. But once I started seriously fishing the small stuff, my success rate with tough, big fish went through the roof.
Eric