Those Who Watch

From Author Wars - https://authorwars.com/publications/those-who-watch-289473.html

Overview:

Title: Those Who Watch
Author: Robert Silverberg
Year: Unknown
Publisher: Signet / New American Library
Price: $0.75
Pages: 143
Binding: Paperback
Type: Novel
Title Reference: Those Who Watch
Notes:
Third printing stated in the middle of the copyright page.
"First printing, April, 1967" at the bottom of the copyright page. No number line.
Cover art not credited, but there is a signature on the cover.
Printed in the US
NOTE: The original note for this publication record read "Though stated 1st printing and having the same date as the 1st printing (#P3160) this a later printing & with a totally different cover." Either the original (unknown) verifier didn't notice the statement of third printing in the middle of the copyright page or he had another (second?) printing which didn't state the printing number aside from the information about the first printing at the bottom of the copyright page.