The Wicked Day

From Author Wars - https://authorwars.com/publications/the-wicked-day-49949.html

Overview:

Title: The Wicked Day
Author: Mary Stewart
Year: 1984
Publisher: William Morrow / SFBC
Price: $5.50
Pages: 314
Binding: Hardcover
Type: Novel
Title Reference: The Wicked Day
Notes:
Date and price from Locus1 Book club edition printed by Doubleday for its various book clubs. Gutter code "N47" indicates a printing in November of 1983. According to Locus1 this was a SFBC selection in June 1984, even though it is not among the selections in the lists provided by SFBC editor Andrew Wheeler posted on the rec.arts.sf.written newsgroup.