Who?

From Author Wars - https://authorwars.com/publications/who-226253.html

Overview:

Title: Who?
Author: Algis Budrys
Year: 1979
ISBN-10: 0839824920
Publisher: Gregg Press
Price: $10.95
Pages: xi+157
Binding: Hardcover
Type: Novel
Title Reference: Who?
Notes:
No dust jacket, as issued Green buckram with gold titles on red background. No printed price, taken from Gregg Press catalog. Photographic reprint of the 1958 Pyramid paperback first edition.