Star Trek: Log Four (1975) contains three TV-script-to-novella adaptations by Alan Dean Foster based on episodes of Star Trek: The Animated Series: "The Terratin Incident," "Time Trap," and "More Tribbles, More Troubles." Here, the Enterprise crew shrinks to Lilliputian dimensions, gets caught in a time warp, and re-encounters Cyrano Jones and his collection of tribbles.
Adapting a 23-minute teleplay to a seventy-page story is no small challenge, and Foster generally does a fair job, giving the stories a more leisurely pace that allows him to build some cosmic atmosphere and bring some depth to the ship and crew. When it doesn't go well, however, things degenerate to a nigh-unreadable slog.
That's the case here with "The Terratin Incident," which is easily the silliest of the three stories here, but which is inexplicably dragged out over half the book. Foster really drops the ball with the logic of his explanations for the phenomenon: if the crew shrinks but retains their original weight, they must also retain their original strength - otherwise they wouldn't be able to move; they should be little super ant people. Instead, they're straining at knobs and building tiny ladders. Also terrible is Foster's embarrassing failure at shamelessly contriving some suspense at the end.
The other two stories are quite a bit better, however. They're also significantly shorter and much better paced. "More Tribbles, More Troubles" is the best, and it's the shortest. One can't help but think that given the fixed length of these volumes, four episodes would be a better number for each than three.
Foster's dialogue, a problem throughout this series, again doesn't ring true for a number of characters in many places. And there are a number of other things that Foster inserts that don't fit with the Star Trek world we know (or even the one we knew in 1975), including a wife for Scotty and Federation mind-wiping.
In short, the other two stories are pretty solid, but "The Terratin Incident" just kills Log Four.