Notes: • ©1968 No other statement of publication or printing • Date from Stuart Wells' Ace notebooks • There is also an ad in the back with code 12-73 • The cover artist is not credited, no visible signature • Cover art credit from dbr.nu. • Interior drawings are credited to Robbins on the title page and ©1968 • There are four pages of maps and ten drawings, one on each chapter's first page • OCLC has no listing specific to this Ace #