This is a revised and updated edition of the reference to identifying the parasites of the freshwater fish of North America. It provides information on public health concerns about fish parasites, methods used to examine fish, and those parasites found only in selective organs or tissues. It lists the known species of each genus, along with reference citations that enable readers to find literature pertinent to species identification, life cycles, and in some cases, control. Each chapter opens with a description of a phylum and its relevant families and genera, followed by a species list for those genera. Drawings illustrate a representative of each genus and are supplemented by photographic examples. Many new parasites of North American freshwater fish have been discovered since the publication of the first edition 30 years ago. For this edition, the author has added new species accounts and revised the taxonomy, expanded descriptions and discussion of the most important fish parasites, provided a glossary to aid non-specialists and updated the reference list to 1992. The volume also has twice as many illustrations as the first edition.