The phylum Nematoda consists of over half a million species of worms that inhabit astoundingly diverse environments. Nematodes can live as obligatory parasites of plants and animals, or alternate a parasitic with a free-living life style. The fact that the vast majority of species are strictly free living often surprises parasitology students, for obviously the highest research priorities in this field have involved parasites of medical, veterinary and agricultural importance. Here Samuel Politz and Mario Philipp contend that some basic questions concerning the biology of the parasite cuticle can be investigated more easily and in greater depth in the free-living nematode Caenorhabditis elegans than in the parasites themselves.