The Entropy Effect
This Star Trek novel is from 1981, but I'm counting it anyway. I've never read many Star Trek novels except for the stuff James Blish wrote, and last year I did Spock Must Die! which was the first one. The Entropy Effect is still pretty early on in the whole thing.
So, the Enterprise has been in orbit around a singularity for weeks, so Spock can study it. It's the first and only singularity ever seen, and it just appeared in space! So it's a big deal. But the Enterprise is called to a super-secret-emergency on a nearby space station, so Spock's work is incomplete and practically worthless. To add insult to injury, the super-emergency is no such thing; they're just needed to take a prisoner to a rehab center -- but this prisoner is Spock's favorite physicist, Dr. Mordreaux, who's been sending people back in time to live.
Then Mordreaux escapes, and kills Kirk! And also Sulu's new girlfriend! And Spock realizes that in order to save the universe, he's going to have to travel back in time to stop all this from ever happening -- because time travel has poked a hole in space-time.
McIntyre has a lot of fun with characters here. Not being limited by the make-up capabilities of a TV show, she loads the security team with interesting species: a leopard-lady with ruby fangs, a massive grey genetically-engineered human woman who's a farmer at heart, an alien woman who only speaks in nouns, and a terrifying red-eyed guy, all under the command of the new security officer, who is teaching judo and romance to Sulu (!).
There is also a lot of Spock and McCoy arguing with each other, and McCoy winds up acting as captain, which he is very bad at. Poor Scotty has a lot of hurt feelings.
It was a decent story, but I did think it was a bit too long -- and featured yet another long-lost love of Kirk's. He does spend some time pondering on his inability to grow up and commit, which is pretty entertaining!
So I've kind of got a chain going here -- first I had two books featuring PIs, and now I have two books featuring time as an important element...wonder if I can keep this going?