The closed worlds
Edmond Hamilton (Author), Jack Gaughan (Illustrator)
"When Morgan Chane and his comrades of John Dilullo's interstellar mercenaries invaded the Closed World of Arkuu in search of a lost Terran expedition, they found a planet of strange menace. Incredibly powerful monsters prowled through Arkuu's dense jungles, and the ghosts of the planet's past haunted its ancient deserted cities. The Arkuuns themselves fought grimly to drive the Terrans away. But at last Chane discovered the Free-Faring, the terrible alien secret Arkuu... and suddenly he knew why no Terran had ever left the Closed Worlds alive."--Pg. [4] of cover
Print Book, English, 1968
Ace Books, New York, 1968