The Final Reflection(TOS) by John M. Ford
- The best star trek book there is. Totally at odds with any trek from TNG onwards since it was written in the eighties.
Where Sea Meets Sky(TOS) by Jerry Oltion
- A very enjoyable cap'n pike exploration tale with a nautical feel. Was part of the "captains table" series, but doesn't require reading any of them.
Federation(TOS,TNG), by Garfield and Judith Reeves-Stevens.
-It spans three eras and focuses on Zefram Cochrane(based on his TOS appearance, First Contact hadn't come out at this point). It feels like the kind of epic "The Motion Picture" tried and failed to be.
Yesterday's Son/Time for Yesterday(TOS) by Ann C Crispin
A couple of great books that focus on spock and a rather surprising relationship.
Spock's World(TOS) by Diane Duane
Deals with Vulcan -its past and what they think it's future should be. Includes an absolutely barnstorming McCoy speech.
Doctor's Orders(TOS) by Diane Duane
Kirk puts McCoy in the captains chair, and things spiral out of control from there. Some great aliens to boot.
The "Errand" series(TOS) by Kevin Ryan
-It's made up of two trilogies, Errand of Vengeance and Errand of Fury, which tell the story of the TOS era conflict between the federation and the klingons, split into basically four viewpoints - a starfleet command officer on earth, a security officer aboard the enterprise who is a klingon infiltrator, an officer aboard a klingon warship, and finally kirk.
One of the best flowing, and most satisfying trek stories I've read.
Book order if you're interested:
The Edge of the Sword
Killing Blow
River of Blood
Seeds of Rage
Demands of Honor
Sacrifices of War
Masks(TNG) by John Vornholt
Away mission on a human colony which eschewed modern technology and cut itself off from earth and ended up going back to a sort of feudal system - but with an interesting twist guided by some of the original colonists. The thing I like most about this book is how well the world and its people is put together. Characterisation(mostly Picard) can be a bit off since this was a very early novel.
Q-Squared(TNG) by Peter David
- An incredibly intelligently written book that weaves together alternate dimensions into a very interesting story.
A Rock and a Hard Place(TNG) by Peter David
- Delves a bit into Riker's past as he goes on leave to help a friend. The other half of the story is his replacement, who is the star of this story. Don't want to go into him as that's the best part of the book.
Dark Mirror(TNG) by Diane Duane
- deals with the mirror universe, written before ds9 went back to it so expect gaping discontinuity - as with Federation, I enjoyed the authors version a lot more then what would later transpire.
Intellivore(TNG) by Diane Duane
- feels like a mystery where the crew are slowly trying to find a creeping horror. the tension in this book amps up very well through to the conclusion.
Possession(TNG) by J.M. Dillard and Kathleen O'malley
- a sequel to a pretty poor TOS book which thankfully isn't necessary reading(I read this one first and never even realised there was a prequel). Great tension as the pressure builds throughout.
Objective: Bajor(DS9) by John Peel
Really fun book, has aliens with a rather interesting fundamental problem.
The 34th rule(DS9) by David R George & Armin Shimmerman
-Brilliant book focusing on quark and how Ferengi tick, with a superb payoff