Behind the Walls of Terra

From Author Wars - https://authorwars.com/publications/behind-the-walls-of-terra-159761.html

Overview:

Title: Behind the Walls of Terra
Author: Philip José Farmer
Year: Unknown
Publisher: Ace Books
Price: $1.50
Pages: 188
Binding: Paperback
Type: Novel
Title Reference: Behind the Walls of Terra
Notes:
• At least the third Ace printing, '76/'77
• Cover art by Bart Forbes on copyright page, cover is also signed
• OCLC has no record for this edition