The first Nick Carter adventure.
Run, Spy, Run: Written by Micheal Avallone and Valerie Moolman. Published in February 1964. This adventure introduces our hero. This book also introduces an archenemy and an fellow spy. Mr Judas, the archenemy, will come back time and time again. Julia Baron is a fellow agent within the organization OCI.
Left picture is the First Printing and the right is the Second Printing
(L) Third Printing and (R) Fourth Printing
Last one is the United Kingdom Edition, both 1st and 2nd printings were the same.
It was common practice to use the same cover art for subsequent printings, as in the cases above.