Cliff Nielsen
Cliff Nielsen is a professional science fiction and fantasy illustrator who has done multiple Star Trek novel covers for Pocket Books. He designed the cover designs of the Prophecy and Change and Tales of the Dominion War anthologies, the Twist of Faith omnibus and the following:

DS9:
 Avatar, Book One
 Avatar, Book Two
 
 This Gray Spirit
 Cathedral 
 Lesser Evil
 Rising Son
 
 The Left Hand of Destiny, Book One
 The Left Hand of Destiny, Book Two 
 Warpath 

Other:
 Pocket TOS – Burning Dreams
 Star Trek: Destiny – Gods of Night
 Star Trek: Titan – Over a Torrent Sea

External link 
 
Nielsen, Cliff