 This is the only "Star Trek" series not to feature regulars from any  other. However, Diana Muldaur (qv) who appeared in "Return to  Tomorrow" and "Is There in Truth No Beauty?" later played the  character of Dr. Katharine Pulaski during Season Two of  _"Star Trek: The Next Generation" (1987)_ (qv). Although she  appeared in almost every episode of the season, she was never  considered a regular.