THE OTHER SIDE OF THE MIRROR [dkvr]
You could call this an anthology of related stories set in Marion Zimmer Bradley's "Darkover" series, or you could call it a Bradley collection, with guest appearances by authors who have written in her other "Darkover" anthologies. The middle 3 stories are by Bradley (only), and make up just over half the book by pagecount - "Everything but Freedom" is a short novel. The 2 by other authors are novella length. All are original to this 1987 book, except the title story by Patricia Floss - which had previous appearance as a pamphlet with a print run of "a few hundred."
(Introduction by Marion Zimmer Bradley)