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.
This older collection features poems for upper elementary to lower middle school children. Many would lend themselves to discussion. It is beautifully illustrated. Some featured poets include Nikki Giovanni, Langston Hughes, James Stephens, and Richard Wilbur.
I guess the point of this book was to explore the range and depth of human emotion through poetry and illustration., but I felt that it missed its mark on both accounts. Some of the poems are fantastic examples but the majority were rather blah. Mayer's illustrations brought some value to the book, but again I think that he could have done better.