Since you were asking about Sulu novels, I forgot to mention Michael A. Martin and Andy Mangels' Excelsior: Forged in Fire. As they also wrote The Sundered and if you enjoyed it, then you should like this too.
While it details the events leading up to Sulu accepting command of the NCC-2000, it also serves as a prequel to DS9's "Blood Oath". Mangels and Martin also offer clever explanations for inconsistencies regarding Trill and Klingon culture (I can't say too much without giving things away).
Recommend ST novels for me, please.
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