Star Trek Crossover
Barbara Hambly's Star Trek novel Ishmael has Spock travelling back to the time and place of Here Come the Brides after discovering a Klingon plot to destroy the Federation by killing Aaron Stempel (spelled "Stemple" in the book) before he could thwart an attempted 19th-century alien invasion of Earth. During most of the story, Spock has lost his memory and is cared for by Stempel, who passes him off as his nephew "Ishmael" and helps him hide his alien origins.
At the end of the story, Captain Kirk discovers that Stempel was one of Spock's mother's ancestors, a reference to the fact that Mark Lenard also played Spock's father Sarek in episodes of the original Star Trek and Star Trek: The Next Generation, as well as several of the Star Trek motion pictures.
Aside from Lenard, other Star Trek guest cast members were series regulars Robert Brown (both of the Lazaruses in "The Alternative Factor") and David Soul (Makora in "The Apple") and semi-regular Carole Shelyne(the visible representation of a Metron in "Arena," whose voice Vic Perrin provided in that installment).
Read more about this topic: Here Come The Brides