When They Come from Space

From Author Wars - https://authorwars.com/publications/when-they-come-from-space-260620.html

Overview:

Title: When They Come from Space
Author: Mark Clifton
Year: 1964
Publisher: Four Square Books
Price: 3/6
Pages: 191+[1]
Binding: Paperback
Type: Novel
Title Reference: When They Come from Space
Notes:
• "Copyright © 1961, 1962 by Mark Clifton" • "First published in Great Britain by Dobson Books Ltd in 1963" • "First Four Square Edition 1964" • Printing not stated, no number line; only known Four Square printing • The artist is not credited, no visible signature on the artwork