Hanging On

From Author Wars - https://authorwars.com/publications/hanging-on-249126.html

Overview:

Title: Hanging On
Author: Dean R. Koontz
Year: 1974
ISBN-10: 0214200388
Publisher: Barrie & Jenkins
Price: £2.50
Pages: 312
Binding: Hardcover
Type: Novel
Title Reference: Hanging On
Notes:
Month from amazon.uk. Price from collectingkoontz.com/guide/hanging-on/, verified from front flap of copy on picclick.com.
Cover artist on back flap in abebooks.com photo.
Copyright page of Archive.org copy has an ISBN, 0 214 20036 8, with the 6 replaced by a handwritten 8; collectingkoontz.com also has the original ISBN. The fixed ISBN seems to be correct since the original is not found online.