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.
The six short stories were solid, the only one that was a letdown was the novelette that wraps up the book. 'Of Missing Persons' is an excellent story and my favorite, about the opportunity for those who have had enough of life to go somewhere else...for real. Very well done. Also: one of the stories, 'Treasure Trove,' also showed up in one of the more modern versions of these collections, 'Alfred Hitchcock's Spellbinders in Suspense.' If you find this book for a few bucks, it's worth grabbing for the short stories.
"Treasure Trove" by F. Tennyson Jesse - two longtime friends in a small farming town undergo a personality change, becoming aggressive and distrustful of each other, after finding a cache of old coins. There is a not unfamiliar idea at the climax of this story, but this is a nice telling of it, with solid writing.
"The Body Of The Crime" by Wilbur Daniel Steele - a, young man Daniel, through a chain of associations, and the recent death of his mother, begins to uncover deep, deep memories from his childhood in pursuit of the question "why is he frightened of his father from time to time?" This was a strange story, told in a style that I can't decide whether to call "modernistic" or "clunky" - could be a mix of both ("clunky modernism"?) all Faulknerian stream of consciousness, strange sentence construction, and the attempt to evoke the slipperiness of memory. It half works.