2 books found:
  Title Year Rating
Star Trek: The Original Series #3: The Klingon Gambit
by Robert E. Vardeman (Oct 1981)
Year: 2268 - Goodreads Rating: 3.32 (869)
After the inhabitants of Alnath II discover an ancient city, crew members of the Enterprise undergo sudden personality changes which effect their ability to protect the starship from an approaching Klingon battle cruiser.
3.32 (869)
Star Trek: The Original Series #12: Mutiny on the Enterprise
by Robert E. Vardeman (Oct 1983)
Year: 2268 - Goodreads Rating: 3.23 (603)
The ship is crippled in orbit around a dangerous planet and a desperate peace mission is stalled. Kirk has never needed his crew more when an alien women casts a spell of pacifism - and now mutiny - over the crew.
3.23 (603)