Star Trek: The Covenant of the Crown by Howard Weinstein
From 1981 comes this novel of adventure. A King has died so McCoy and Spock must help the Princess literally find her crown on an ice planet. Elsewhere Kirk must deal with mustache twirling Klingons. This is a good novel because of the Spock/McCoy interaction.There are plot holes and plot illogic (how can a world that has never achieved spaceflight be a quadrant wide trading partner and how was it eligible for first contact?) However the Spock/McCoy double act is so delightful you can overlook the plot holes and the fact that important Starfleet info is sent on cassette tapes.