Volume 2 offers a unique classification of two large suborders of nematodes: Oxyurata and Ascaridata. A total of 748 species, constituting 146 genera and 21 families, distributed among 4 superfamilies - Oxyuroidea, Subuleroidea, Cosmocercoidea, and Atractoidea - are included in the suborder Oxyurata. Another 424 species, included in 44 genera and 5 families, distributed in 2 superfamilies - Ascaridoidea and Anisakoidea - comprise the suborder Ascaridata.The present work is unique not only because it represents the first classification of all the known memgers of the suborder Oxyurata, and a radical revision of the taxonomy of the suborder Ascaridata, but also for defining taxonomic features for every taxon based on both the literature published in the last 100 years and extensive personal research. Helminthologists will welcome this book for two reasons: its obvious value in systematizing the oxyurids identified up to 1950 into a cohesive, scientifically well founded taxonomic subdivision of Nematoda, and as a collation of all the material published worldwide on members of the suborder Oxyurata available to the authors at that time.