Barry St. John

Barry St. John was a 23rd century Human male. By the late 2270s, St. John was serving in Starfleet as a security guard aboard the USS Enterprise (NCC-1701).

St. John accompanied Admiral James T. Kirk, Dr. Christine Chapel, Lieutenant Lex Nakashima, and two other security people, Sergeant Juan Aragonés and Marta Bergstresser, on a landing party to Charlotte, one of the three moons of the planet Cathy in the Novak system. They explored a cave system containing one-third of the lost treasure of Vulcan. According to some accounts, they made first contact with a primitive species called the Teela who inhabited the caves. Also in some accounts, St. John disappeared after a battle with the Teela and was never seen again. According to other accounts, he was found unconscious in a rock crevice and sent back to the Enterprise for treatment. (TOS novella: The Vulcan Treasure)

St. John's disappearance appears to be an error on the author's part due to the complexities of the book's "plot-your-own" format.