In the previous summary post, I discussed James Blish's adaptations of TOS. The other major set of adaptations are the Star Trek Log series by Alan Dean Foster, which adapted Star Trek: The Animated Series:
Compared to Blish's series, these are very nice. Foster has more than twice as many pages per story, and only half as much story to adapt, so he's able to add a lot to the scripts–the characters' thoughts, narration expanding on the speculative elements, whole new events added to the story. And the last four books in the series adapt just one episode each, so Foster extends the stories with substantial original material.
There will still be some novelizations after this series–the movies, a few episodes of the later series–but as this series concluded, the publication of original Trek stories started picking up to several per year, half a dozen by the mid eighties, and at least one per month by the late eighties.
Unlike Blish's adaptations, these books are worth a read for modern fans.