This volume reflects the latest developments in the research of a global community of rotifer researchers, who came together at Illmitz, Austria in 2003. Contributions are manifold and span fields from phylogeny and evolution of the phylum Rotifera to practical aspects of aquaculture and ecotoxicology. Major issues include phylogeny and evolution, genetics and molecular ecology, new aspects of rotifer anatomy through the application of confocal laser-scanning microscopy, anhydrobiosis, long-term studies in lakes and rivers, population dynamics and community ecology, trophic relationships between copepods and rotifers, alongside biodiversity studies based on classical taxonomic concepts and molecular approaches. Although primarily focussed on one taxonomic group, the scientific outcome of this meeting is of relevance to the study of other aquatic microinvertebrates as well.