In November 1977, over two years after the previous entry in the series, a new book of Trek novelizations was published: Star Trek 12.
Blish died in July 1975, so this final volume was completed by his wife, Judy (credited as J. A. Lawrence). In fact, she had been working on the series for several years, by this point:
How I got involved was that somewhere around the seventh or eighth book, Jim was beginning to feel a breeze from the Angel's wings and an urgency to attend to his own work. He didn't have the energy to do both; he was not very well. Rather than abandon the project, my mother, a long-term professional writer in other fields, and I, who had begun selling my own science fiction (SF) stories, offered to write them, and he would do the quality control on our production. We tried it and it seemed to work okay. (In some of those later stories you can see the fine romantic hand of my mother who was strong on the mushy love stuff.) After Jim died, I told all this to then editor Frederik Pohl, who rather doubtfully allowed me to continue. But he found the result acceptable, [so Star Trek 12] has both our names on it.
The Enterprise is sent to find out what happened to John Gill, a historian assigned as a cultural observer to the planet Ekos. Gill is known to both Kirk and Spock: he had been Kirk's instructor at the Academy, and Spock had learned history from a history book Gill had written.
As they arrive at the planet, a nuclear warhead is launched at the Enterprise. They destroy it, but upon beaming down, Kirk and Spock discover things are much worse than they had feared: the planet has modeled itself after Nazi Germany, and is prosecuting a war against its (more technologically advanced, but peaceful) sister planet, Zeon. It comes out: the planet's Führer is none other than John Gill.
Kirk and Spock (mistaken for Zeon infiltrators) are captured, and escape, and ultimately make their way into the Führer's presence, only to find that he is heavily drugged and the real power controlling Ekos is the Deputy Führer, Melakon. Gill had hoped to use the Nazi social system to unite the planet, but the system was too open to abuse, and the whole world suffered for it.
McCoy brings Gill out of his drug-induced stupor long enough for him to publicly denounce Melakon, before Gill is shot and killed by Melakon. But his words were enough: there will be peace between Ekos and Zeon.
This story isn't too bad, but on TV its main attraction was probably the excuse for a costume show. It's passable, if forgettable, as a short story.
Kirk, Chekov, and Uhura are mysteriously transported off the Enterprise, and find themselves on the planet Triskelion, where they are to become slaves of the 'Providers' who will give them food and other necessities, in exchange for the 'thralls' engaging in bloody combat to provide these 'gamesters' with something to bet on.
Kirk and co. aren't pleased to be taken as slaves, and aren't interested in participating in the training offered, which gets them in trouble. However, Kirk is able to convince the Providers to make a big bet with him: he will fight off three of their chosen champions, alone; if he wins, the providers will free all the thralls and teach them to be self-sufficient; if he loses, then not only he, Chekov, and Uhura, but the entire crew of the Enterprise will become their thralls.
Needless to say, Kirk wins.
This is another story that worked better on screen. It pretty much relies on the costuming and action, which just don't translate well to this adaptation.
The Enterprise responds to a distress call from the planet Triacus. They arrive to find the adults from the research expedition there are dead, but their children are alive and well and seemingly don't care that their parents have been killed.
They collect the children to take them to Starbase 4, but once the children are on board, a sinister truth is revealed: the children are in contact with a being calling itself Gorgan, which is responsible for killing their parents. Gorgan has some power of mental influence, and he and the children are using it to direct the ship to the planet Marcos XII. If they reach the planet, millions may be killed.
Kirk shows the children video recordings of them playing with their parents, back on Triacus followed by images of their parents, dead, and their graves. This shocks the children out of trusting Gorgan, and he is banished.
The episode this story is based on was pretty dreadful already, and it just isn't improved by the adaptation.
The Enterprise encounters a strange cube, moving through space without apparent means of propulsion. When it begins emitting deadly radiation, Kirk orders it destroyed. Later, they encounter the ship from which the cube originated: the Fesarius, the flagship of the First Federation. Its commander, Balok, indicates that the Enterprise will be destroyed for behaving violently.
In the end, desperate, Kirk tries bluffing: he claims the all Federation starships contain a substance, corbomite, which will destroy any attacking ship. Balok decides instead to tow the Enterprise, but it is able to escape. In doing so, Balok's ship is–apparently–badly damaged, and when Kirk, Spock, and McCoy transport over to render aid, Balok reveals that it was all a ruse, to test them, and they can look forward to cordial relations.
The subplot with Bailey seems a bit overdone–he's a little too hysterical–but on the whole the story holds together well. It's a classic bit of Trek. It's a little simple, though: the Enterprise is threatened. How? By someone threatening the Enterprise.
The crew of the Enterprise needs shore leave, so the find a likely planet. However it seems that whatever people imagine appears–whether that's a harmless scene from Alice's Adventures in Wonderland or a deadly attack.
In the end, it turns out that even the deadly attacks were harmless: the planet is designed as a place for recreation for an advanced species, and any harm done will be repaired. Thus reassured, the crew has shore leave as planned.
This is a dull story. Its charm was in seeing our heroes reacting to seeing the white rabbit, or watching Kirk get some revenge on a bully, but it just doesn't hold any interest in text.
Conclusion
This volume has the misfortune of adapting one quite bad episode and three that rely on visuals for their best effect. The writing is fine, but if the source material doesn't hold up, then there's nothing Blish (or Lawrence) could do to save it. "The Corbomite Maneuver" is worth a read, for fans, but the rest is best left to history.
There is one nice touch: the book ends with appendices listing all the episodes, in which season they appeared, who wrote them, and in which book they are adapted. Handy!