Knowledge in the field of parasitology must be kept at a high level and up to date in order to fight a parasitosis as quickly and effectively as possible. The third edition of the “Encyclopedia of Parasitology” contributes to these goals in several ways: the number of entries has been increased by about 30%, the content has been even more improved by adding more tables and figures. The extensive linking between definitions and essays facilitates information within a minimum of time. More than 40 international contributors, who are well known specialists in their fields, give a comprehensive review of all parasites and therapeutic strategies in veterinarian and human parasitology. The third edition is now presented as two volumes in A-Z format and additionally in an electronic online version.