The X Factor

From Author Wars - https://authorwars.com/publications/the-x-factor-553038.html

Overview:

Title: The X Factor
Author: Andre Norton
Year: 1973
Publisher: Ace Books
Price: $0.75
Pages: 158
Binding: Paperback
Type: Novel
Title Reference: The X Factor
Notes:
• No printing or edition stated
• Dated by ads in the back which differ from the 1970/1972 Ace printings of the same catalog #
• Ads are 24C and 25B which only appeared in very late 1972/early 1973
• Possibly Ace changed only the ads from the 1970 printing and missed advancing the catalog # to 92552 [as of 2015-12-27 there is NO ace edition printing with 92552 of this or any other title]
• The copyright page credits Jack Gaughan for the cover but the style and lack of visible signature makes that questionable; interior art has Gaughan's "JG" on all pieces
• #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"