When I was reviewing the episode Star Trek: The Original Series – All Our Yesterdays, I remarked that it would have been interesting to see a follow-up on that story where Zarabeth gives birth to Spock’s child. Lo and behold, I was pointed to this book, Yesterday’s Son.

Two years after events in All Our Yesterdays, the Enterprise is studying archaeological evidence retrieved from the planet Sarpedion when a member of the crew finds evidence in a cave that there was a Vulcan on the planet. Knowing what happened between himself and Zarabeth in the cave, Spock reaches the conclusion that way back in the distant past Zarabeth gave birth to his son. Spock feels an obligation to the boy and travels to Vulcan to have T’Pau petition the Federation for him to use the Guardian of Forever to bring his son out of the past. Of course, neither Captain Kirk nor Doctor McCoy will let Spock go on this journey alone.

They travel through the Guardian and eventually meet Zar, the son Zarabeth gave birth to many years earlier. Zar is much older than Spock was expecting, but they bring him back to their present-day regardless. Spock intends to teach Zar in the Vulcan tradition. However, Zar has been on his own for some time and is actually only one-quarter Vulcan, complicating matters greatly.

Spock treats Zar in a very stand-offish manner. Zar is looking for Spock to be the man his mother described to him. Of course, that man was a regressive Vulcan, made more emotional by the effects of traveling back in time. Spock is nothing like that. Although Kirk and especially McCoy try to help the young man adjust, it’s a father’s love he is looking for and Spock is not forthcoming with that.

Meanwhile, the Romulans have taken notice of all of the activity on the planet Gateway, which houses the Guardian of Forever. The Federation went to great lengths to try to protect the planet without seeming like they were protecting it, but the Romulans weren’t fooled. They know there is something of great value on the planet, and they intend to have it.

Although short at just 140 pages, Yesterday’s Son packs a lot between the covers. It’s mostly Spock’s story and deals with his inability to admit to an emotional failing on his part, seemingly a long time ago. He feels an obligation to Zar, but doesn’t speak of love or any attachment. He’s unwilling to tell his parents about the child as well. When he travels back to Vulcan for the audience with T’Pau he goes to great lengths to keep his visit a secret from them. He’s unwilling to admit that he is Zar’s father to anyone on the Enterprise except for Kirk and McCoy, who know the truth. Zar picks up on this and thinks it’s due to Spock being ashamed of him, but Spock is ashamed of himself and taking it out on Zar, although he doesn’t see it that way.

If there’s one thing I could say I wasn’t crazy about, it was the ending. Although it had to be something like this to be accepted as canon in the Star Trek Universe, it felt like a lot of story development, character development, and potential was wasted. However, there’s another book following this one. Author A.C. Crispin actually intended originally to write a trilogy, but if that’s the case it was never completed.

I enjoyed Yesterday’s Son quite a bit. It’s easily one of the better Star Trek TOS books I’ve read in a while. Crispin has a good grip on Spock’s character and develops Zar nicely to compliment that. If you’re a fan of continuing some of the stories seen in the Original Series, I strongly recommend picking up this one.