What do we mean by freshwater invertebrates? -- Why study freshwater invertebrates? -- Classification of freshwater invertebrates -- Fundamentals of freshwater ecology -- Fundamentals of freshwater invertebrate biology -- How to study freshwater invertebrates -- Identification of different kinds -- QuickGuide to major groups of freshwater invertebrates -- Flatworms -- Leeches -- Aquatic earthworms -- Snails -- Mussels, clams -- Water mites -- Crustaceans -- True bugs -- Water beetles- adults -- Dragonflies, damselflies -- Stoneflies -- Mayflies -- Dobsonflies, fishflies, hellgrammites, alderflies -- Caddisflies -- Water beetles- larvae -- True flies -- References on identification of different kinds of freshwater invertebrates -- Information about different kinds -- Flatworms -- Segmented worms. Aquatic earthworms -- Leeches -- Mollusks. Snails -- Mussels, clams -- Arthropods. Water mites. Crustaceans. Aquatic sow bugs -- Scuds, sideswimmers -- Decapods -- Aquatic insects. Mayflies -- Dragonflies, damselflies -- Stoneflies -- True bugs -- Dobsonflies, fishflies, hellgrammites, alderflies -- Water beetles -- Caddisflies -- True flies -- References on information about different kinds of freshwater invertebrates. Provides information of many groups of invertebrates commonly found in the streams, lakes, ponds, and other freshwater environments of North America. Section 1 provides background information on the biology and ecology of freshwater organisms and environments and explains why and how invertebrates can be studied, simply and without complex equipment, in the field and the laboratory. Section 2 describes nearly 100 of the most common groups of invertebrates, and for each group a whole-body color illustration is provided along with brief text pointing out the most important features that identify members of the group. Section 3 contains in-depth descriptions of the life history, behavior, and ecology of the various invertebrate groups, and explains their important ecological contributions and relationships in humans.