In my opinion, 'The Eugenics Wars: The Rise and Fall of Khan Noonien Singh' is among the best. It gives a detailed backstory to one of the most iconic villains in Star Trek. It's full of intrigue and adventure. On the other hand, 'Strangers from the Sky' has been criticized as being one of the less - appealing novels. The pacing is slow and the story doesn't seem to add much to the overall Star Trek lore.
The 'New Earth' series had its detractors. The plotlines in some of the books in this series were seen as rather convoluted. For example, some of the characterizations didn't seem to stay true to the original Star Trek characters. It was like they were trying to do too much with the new setting and lost sight of what made Star Trek great in the first place.
Good Star Trek novels are those that can make you feel like you're part of the crew. 'The Entropy Effect' by Vonda N. McIntyre does this well. It has a great mystery and the characters are well - rounded. In contrast, 'Prime Directive' by Judith and Garfield Reeves - Stevens is often considered bad. It takes the concept of the Prime Directive and twists it in a way that makes it seem more like a plot device than a fundamental part of the Star Trek philosophy.
In my opinion, 'Dyson Sphere' is also a contender for the worst Star Trek novels. The science in it was a bit iffy. It didn't really hold up to what we know about the Star Trek universe's science. And the story was just not that interesting. It lacked the excitement and the thought - provoking elements that good Star Trek novels usually have.
Well, it's really subjective. But some fans might consider 'Spock's World' by Diane Duane as one of the worst. The plot can be a bit convoluted and the characterizations not as strong as in other Trek novels. It kind of strays too far from what makes Star Trek great in terms of its core values and the way the characters interact.
I think 'Vulcan's Glory' could be considered one of the worst. The story just doesn't seem to flow well and the characters don't have the same charm as they do in the TV shows or better - written novels. It lacks the sense of wonder and discovery that is typical of Star Trek.
Well, opinions on the 'worst' can vary greatly among fans. One that often gets criticized is 'The Final Reflection' by John M. Ford. Some fans didn't like its complex and convoluted plot that deviated too much from the typical Star Trek feel. It introduced a lot of new concepts and species in a rather clumsy way, making it hard for some to follow.
Well, 'Ishmael' by Barbara Hambly is considered among the best. It offers a different perspective as it focuses on a character who has a complex relationship with the Star Trek universe. Also, 'Final Frontier' by Diane Carey is quite good. It has a lot of action and really captures the essence of the Star Trek spirit with its adventure and exploration themes.
Well, 'I, Robot' by Isaac Asimov is often considered among the best Star Trek novels. It has thought - provoking ideas about robotics and artificial intelligence that fit well within the Star Trek themes. Then there's 'Foundation' by the same author. It's known for its grand scope and exploration of future societies, much like what Star Trek does. Also, 'Stranger in a Strange Land' by Robert A. Heinlein has elements that resonate with Star Trek's exploration of different cultures.
I think 'Vulcan's Forge' is one of the worst. It had some really cheesy dialogue that didn't seem to fit the Star Trek style. The plot also had some holes in it. For example, some of the character's actions didn't seem to have proper motivation, which made the whole story feel a bit disjointed.