The Aphelenchida, Longidoridae and Trichodoridae are groups of nematodes that include almost 1,000 species from some forty genera. A number are of known agricultural importance, both in their own right as parasites of fungi or higher plants and/or as vectors of certain plant viruses. While monographs exist on the systematics and taxonomy of a number of nematode groups, no recent volume covers the three groups included here. This book aims to provide a practical, working guide to the taxa of the Aphelenchida, Longidoridae and Trichodoridae, in such a form as to facilitate usage by both specialist taxonomists and general nematologists. Keys to generic level are included, each genus being diagnosed, illustrated and provided with a comprehensive list of nominal species and, where appropriate, synonyms. General notes on the bionomics and distribution are appended and some 22 species, mostly those of economic importance, are individually described in greater detail. In addition, a general introduction to each of the three systematic sections includes an historical review, basic morphology and a summary of the bionomics. With a comprehensive bibliography, the book is a unique guide to these groups of plant parasitic and free-living nematodes.