Gather, Darkness!

From Author Wars - https://authorwars.com/publications/gather-darkness-324278.html

Overview:

Title: Gather, Darkness!
Author: Fritz Leiber
Year: 1996
Publisher: The Easton Press
Pages: 240
Binding: Hardcover
Type: Novel
Title Reference: Gather, Darkness!
Notes: Unicorn endpapers used for Masterpieces of Fantasy.
Leatherbound, gilt page edges, silk marker.
No price given, no ISBN, no credit for cover artist. Collector's note "The Other Side of the Mirror" for this title written by James Gunn laid in. Also laid in is a series bookplate.