"Sparkling like a three-dimensional snowflake in the depths of space, Gemworld once was one of the Federations greatest marvels. Six different alien races coexisted peacefully on an artificial world composed entirely of crystal - Until they very substance of Gemworld began to multiply out of control, tearing the world apart. Now the entire planet - and the Starship Enterprise as well - faces total destruction. "
If the description on the back cover doesn't convince you, I don't know what will. Stop by the Barrett Memorial Library fast, there is a huge Star Trek Sale going on now. Star Trek books for as low as 25 cents, you can't beat that.