The Rocket's Shadow

From Author Wars - https://authorwars.com/publications/the-rockets-shadow-155891.html

Overview:

Title: The Rocket's Shadow
Author: John Blaine
Year: Unknown
Publisher: Grosset & Dunlap
Price: $1.25
Pages: vi+209
Binding: Hardcover
Type: Novel
Title Reference: The Rocket's Shadow
Notes:
No printing date, bought new in the mid-1960s. Price from gold foil sticker attached to the book. Grey casewrap cover with color illustration on the front. Back cover has an illustration and a list of 20 series titles printed in red. Spine shows the series number and the catalog number. The cover illustration appears to be the same as the one on the dust jacket front cover of the first hardcover Grosset & Dunlap edition. Cover artist is not credited. Endpapers have a two-page map printed in blue and white titled "Spindrift Island". Map artist is not credited.