'Subject-specific advice from five leading professionals - Eamonn McCabe, Steve Shipman, Bjorn Thomassen, Matt Hoyle and Mark Cleghorn - that specialize in portrait photography. Chapters include working with people, posing, indoor lighting techniques and weeding photography plus key Photoshop processes and printing tips.
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.