Chain of Attack isn't one of the best Star Trek books ever written, nor is it the worst. It falls in the middle, not great, not awful, an OK read, but not one I'd pay full price for.
Captain Kirk and his crew are exploring gravity anomalies with fancy new sensors, when they are suddenly thrown millions of parsecs far from the known universe into another galaxy! Shades of Voyager (and this one was written in 1987). Of course, when they arrive, they find themselves in the middle of an interstellar battle where nobody knows who is his real enemy is and, as usual, they have to stop the fighting and figure out how to get home (where are they and where is home?).
To add insult to injury, Kirk is saddled with one of the most annoying characters every created in the Star Trek universe. Dr. Crandall is a civilian observer and obnoxious pest - why he is there is beyond me. He is neither original nor believable and was pretty well pointless. The concept that the "outsider" from off the Enterprise, whether an Admiral from Starfleet or a civilian scientist, proves to be just as difficult and troublesome as always. This subplot is done so often in Original Series episodes and books that it is really a waste of paper.
The trip to the other side of the galaxy, the diplomatic adventure, (Kirk will never be the negotiator that Picard is) and the voyage home was a good enough story in itself and reading it now following the end of the Voyager adventures, makes it a relatively worthwhile book. Adding Crandall did the novel as a whole a disservice and if you can read around him, do so.
Title: Chain of Attack