The Rider

From Author Wars - https://authorwars.com/publications/the-rider-46167.html

Overview:

Title: The Rider
Author: Edgar Rice Burroughs
Year: Unknown
ISBN-10: 0441722822
Publisher: Ace Books
Price: $1.95
Pages: 154
Binding: Paperback
Type: Novel
Title Reference: The Rider
Notes:
Originally published in 1918 is All-Story Weekly as "H.R.H" The Rider
"Cover Painting by Frank Frazetta" on copyright page, the artwork is also signed
Also appears in the Ace box set "Edgar Rice Burroughs".