NOTE: Amazon is combining reviews of various "Log" books - this is a review of Log One.
Star Trek: Log One (1974), by Alan Dean Foster, contains three novellas adapted from the first three episodes of Star Trek: The Animated Series: "Beyond the Farthest Star," "Yesteryear," and "One of Our Planets is Missing." Here, the crew investigates an ancient derelict ship, Spock travels back in time to save his child self, and the Enterprise is swallowed by a planet-eating cloud.
Each novella is about sixty pages, and generally, this is a good length for this material, although there's quite a bit more setup, especially for "Beyond," and the pacing tends to be on the leisurely side. Foster has a narrative flair for the dramatic, and his characters often ponder grand cosmic thoughts. The overall effect is a different tone and feel from either The Original Series or TAS. The stories themselves are solid if not spectacular; "Yesteryear" was easily the best TAS episode, and, with the most character focus of the three, it's the best story here, too.
Foster's characterization is adequate at best, and the dialogue doesn't always ring true. The Kirk-Spock-McCoy interplay isn't on the level that Trek fans will likely expect, and tends to lack both charm and humor. Kirk himself is uncharacteristically awkward at times, while the Spock-McCoy exchanges are more immature and less good-spirited than what we saw on either TOS or TAS.
The only scientific nitpick here is in "Beyond," where the characters regularly experience sound on a ship with no atmosphere (although in fairness, every iteration of Star Trek going back to TOS has abused this).
On the whole, Star Trek fans should find Star Trek: Log One reasonably readable and enjoyable, whether they've seen TAS or not.