The X Factor

From Author Wars - https://authorwars.com/publications/the-x-factor-259481.html

Overview:

Title: The X Factor
Author: Andre Norton
Year: 1970
Publisher: Ace Books
Price: $0.75
Pages: 158
Binding: Paperback
Type: Novel
Title Reference: The X Factor
Notes:
- No printing or edition stated
- Date from OCLC
- Pseudo SBN 441-92551-075 on spine can be converted to ISBN 0-441-92551-0.
- Ads list #A-10, #G-630, and #G-634 (all published in 1967) as the last item on each page. A comparison of the ads in #G-646 has confirmed that this edition was published with reprinted ads from the Original #G-646 edition dated 1967.
- The copyright page credits Jack Gaughan for the cover but the style and lack of visible signature makes that questionable.
- #92551 and #92553 (another ace printing of the same title) are the only two 5-digit Ace publications before 1975, according to a bibliography by Helen-Jo Jakusz Hewitt published in 1975 publication "The Book of Andre Norton"