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.
An amazing anthology of just enough fright to keep you on your toes! It's also a fairly easy and quick one day read if that happens to be what your heart desires along with its fright for the day. My favorite is the Villasca Axe Murder House story. I have been to the house, I love the paranormal and though it was closed just standing in front of it you can't help but believe this story could more than come true. So, cuddle up, turn off the lights, read by a dim light and let your mind slip into a world of nightmarish dreams. Oh, and don't forget to Sleep Tight!