The Changeling

From Author Wars - https://authorwars.com/publications/the-changeling-618802.html

Overview:

Title: The Changeling
Author: Zilpha Keatley Snyder
Year: 1976
ISBN-10: 0718822226
Publisher: Lutterworth Press
Price: £3.20
Pages: 210
Binding: Hardcover
Type: Novel
Title Reference: The Changeling
Notes: 1st UK ed. probably (earliest found at WorldCat)

Publ date, cover image from Amazon UK 2017-05-21, with unusually limited "Look Inside!" that shows "Jacket design by Mary Dinsdale" over this ISBN and price -- "First published in Great Britain, 1976" "Look Inside!" is unusual so all data from Amazon may be doubted