The Lincoln Library of Essential Information, Edwin Valentine Mitchell, editor. Frontier Press, 1955 22nd edition, two-book set, 2,112 pages and updated through "The Atomic Age." Books; Two volume set , faux leather covers, gold lettering to covers and spines. Printed on special paper that has preserved well probably due to all page edges being gold. Profusely illustrated with color and black and white photos, maps and drawings, illustrated endpapers. Books purpose is to set into one book all the essential information the common man might need for self education and is written in plain layman's terms. Revised and updated from 1924 through at least the 70's.
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 Lincoln Library of Essential Information is one of the most superior reference books I have read. Every faucet of knowledge is detailed, encyclopedic lectured, further explained through supplementary indexes.
This book has my soul shouting out "This is how reference books are suppose to be published! Learn from this modern publishers! Learn from this editors!, you whom insist on "less is more" when editing a book, lessening paragraphs to "encourage readability".