Star Trek--TOS #39: Time for Yesterday (Crispin, AC)

Rating: 3
Year: 1988
Genre: Sci-fi/Star Trek
Read again? In a few years.

This sequel to Yesterday's Son takes place just before "The Wrath of Khan."

Stars are dying. Time is running too fast and making them burn out! Kirk, Spock and McCoy--three of only a few people in the Federation who know what the Guardian of Forever really is--are sent to try to find out why it's suddenly wreaking havoc with the galaxy's time-stream.

They take a psychic Space Wallaby, the best candidate for talking to the Guardian. It zaps her brain, so there's only one thing to do: go back 5,000 years, find Spock's son Zar (who once talked psychically to the Guardian), and bring him back to the present! Great Spock!

There's a snag. For Zar, it's only been about 15 years since the last time he saw them. He's been using the time to build a little kingdom in a pleasant valley. But he's surrounded by enemies! When they find him, Zar is marshaling his forces, preparing to die in battle.

A much better book than its predecessor. More twists and turns, better characterization. But the science sucks, even for a "Star Trek" novel.

Howlers:
"When a star burns all of its hydrogen, it dies." (page 33). WRONG. Stars aren't really "burning" hydrogen--they're doing nuclear fusion, where hydrogen atoms are fused into helium atoms and energy. If it's a sun-sized star, once it has "burned" through a certain amount of its hydrogen, it expands to become a red giant (there's more to it than that, but dammit, Jim, I'm a book reviewer, not an astronomer!).
Crispin's got stars going nova all over the place and uses that as the "ticking clock" gimmick that's supposed to push the plot...but they've got a freaking TIME portal they could use to minimize that problem.

One point off for the sucky science--and another for the Space Wallaby.