I'm asking about books not about Star Trek but use the universe as a backdrop. For example a detective story on Alpha Centauri, a hospital drama on Federation Earth, a romance on Kronos
Except that Star Trek
is the universe, not any one part of it. Every sequel, prequel, and spinoff series has included Star Trek
as part of the title. Enterprise
was without it for the first two seasons, but then it was retitled Star Trek: Enterprise
for the name recognition. If all those different series set in different times and places and featuring different people were all Star Trek
, then there's no real way to define something that's part of the universe but doesn't fall under the ST label.