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.
I read this book for my 8th grade English class. There are plenty of stories and poems from the Holocaust Era, giving the reader a true understanding of what it was like to be in the Holocaust. It gives great details on the day to day struggles that Nazi victims had to go through in concentration & death camps and ghettos. Really recommend this book for assignments in school.