Jas Heriot Duke [1939-1992] was a cult figure in the Australian performance poetry scene, an Anarchist and political activist and an actor in many underground movies by filmmaker Jeff Keen. He discovered visual and sound poetry, along with the Dada movement, in the sixties. In the late seventies he became an active member of Collective Effort Press and was involved in the publication of this first anthology of Australian visual poetry. Contributors include Alan Riddell, Sweeney Reed, Richard Tipping and Lindsay Clements, plus others.
Various is the correct author for any book with multiple unknown authors, and is acceptable for books with multiple known authors, especially if not all are known or the list is very long (over 50).
If an editor is known, however, Various is not necessary. List the name of the editor as the primary author (with role "editor"). Contributing authors' names follow it.
Note: WorldCat is an excellent resource for finding author information and contents of anthologies.