Flatworms are an extremely widely studied group of organisms reflecting diverse forms, widespread distribution and highly specialised life history strategies. This text links all flatworms in a phylogenetic context and shows how these diverse disciplines can be brought together under the umbrella of phylogenetics and systematics. The book should be useful for readers working on flatworms in various fields.

This is the third of three volumes of Keys to the Trematoda, a series on the systematics and identification of the Class Trematoda. It covers five superfamilies with the Order Plagiorchiida and the family Didymozoidae, with the keys for their identification at the family, subfamily and generic levels. It also includes a key to all dignean superfamilies, including those treated in detail in volumes one and two.