Free living nematodes, abundant and ubiquitous inhabitants of marine benthic habitats, are generally considered to be notoriously difficult to identify. This belief has resulted in their receiving irregular and inadequate attention from ecologists. However, in practice, the difficulty lies not in their supposed morphological uniformity, which is in any case erroneous, but in their great diversity coupled with a fragmentary taxonomic literature. It is suggested that the more widespread availability of pictorial keys would facilitate identification of, and generate interest in, this important group of organisms. The means of constructing such keys is discussed using examples from recent publications.