This volume contains selected papers from the 9th Symposium on Aquatic Oligochaeta, 6–10 October 2003, Wageningen, The Netherlands. 18 contributions deal with the biology of aquatic oligochaetes, and represents a mixture of the fields of taxonomy, anatomy, morphology and physiology, life history, ecology, sludge studies and toxicology. This wide scope is in line with the recent trends in oligochaete research, with a special interest in sludge studies.

Research teams from France, Japan, United States, Czech Republic, The Netherlands, Spain, Italy, Germany, Hungary and China present the latest developments on annelid studies and also reflect a balanced mixture of geographical areas, as well as biological topics.