Devil World: Gordon Eklund

Star Trek Original series Book 12. The Enterprise is en route to Heartland - a mysterious planet populated by a small but terrifying race of demonic beings. Heartland - where Kirk falls in love with a beautiful, mysterious woman with a fatal secret, and where the rest of the crew will be challenged by an awesome, disembodied intelligence, more powerful than any other force in the Universe. Cover art by Chris Moore.