"Flashback" was another Trek episode that I read before seeing the actual episode. I remember when I first saw the episode it took me a while to realize that it was a single episode. I thought, by the book, that the story would've been a 3-part episode, instead of a single episode.
But with the last few novelizations ("Endgame", "Broken Bow", "Shockwave", "The Expanse" & the 2009 movie) I've found that there hasn't been as much "meat" in the stories as there used to be with the older novelizations (STV, STVI, "Descent", "Caretaker", "Flashback", "Trials And "Tribble-ations"---which, for a tiny book managed to get quite a bit in). It seems like, since Marco Palmieri took over as editor, the novelizations had to stick squarely to the script with very little room for exposition and added plots outside what was shown on screen. I remember how in "Day Of Honor" Michael Jan Friedman was able to add the entire plot about the Doctor fining a holiday that he could celebrate.