More than a small hatch guide, less than a "tomb". Fresh Water Entomology, by Patrick McCafferty is the best $50. I've ever spent on fishing. I recommend it as a toilet book, and much like the "Tao", wherever you open it, there is something you need to know.
Cool feature is some parts are directed to ecologists and fishermen. Mine is dogeared and water stained, and goes with me all the time. This is a "life sport" and there is a lifetime of info provided. (Nice illustrations too.)