This epic anthology on Swami Vivekananda is offered by the Ramakrishna Mission Institute of Culture on the 150th anniversary of his birth. Most of the contributions were written especially for this volume, though a few were felt important enough to be reprinted from previous publications. The writers include Swami Gambhirananda, Swami Tathagatananda, Swami Atmarupananda, and Swami Tyagananda. Included are two sections of photographs of Swami Vivekananda and his times.
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.