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.

Librarian note: There is more than one author in the GoodReads database with this name Janet Kaye Fox was an American fantasy and horror writer, poet, teacher, and founder-editor-publisher of the now-defunct Scavenger's Newsletter. She lived in Osage City, Kansas. (source: Wikipedia) Also wrote under the name of Alex McDonough

Glen Cook was born in New York City, lived in southern Indiana as a small child, then grew up in Northern California. After high school he served in the U.S. Navy and attended the University of Missouri. He worked for General Motors for 33 years, retiring some years ago. He started writing short stories in 7th grade, had several published in a high school literary magazine. He began writing with malicious intent to publish in 1968, eventually producing 51 books and a number of short fiction pieces. He met his wife of 43 years while attending the Clarion Writer's Workshop in 1970. He has three sons (army officer, architect, orchestral musician) and numerous grandchildren, all of whom but one are female. He is best known for his Black Company series, which has appeared in 20+ languages worldwide. His other series include Dread Empire and and the Garrett, P.I. series. His latest work is Working God’s Mischief, fourth in the Instrumentalities of the Night series. http://us.macmillan.com/author/glencook