Reading the Water is written by Dave Hughes and he does an excellent job describing how to find that 10% of water where the fish are holding rather than you waste your time fishing the 90% of water where there are no fish to be found!
Dave does well in explaining the basic water types you normally find in a river like: riffles, runs, pools, dead water, etc. Mr. Hughes explains in extreme detail and easy to understand language for the beginner and advanced fly fisherman alike. He goes on to explain the different types of aquatic insects found in each type of water and why it will be found in just certain types of water over others (e.g. why certain nymphs are found primarily in the riffles and others more in pools.
He makes it clear where the fish will be in each type of water, what insect types you will find in each type of water and what techniques works best to catch the fish in each water type. I find this an all-around comprehensive reference book for both the beginner and advanced fly fisherman filled with many tips and techniques that can use every time when out on a fishing trip! Get this book you won’t be sorry. 🙂