Yeah, but a nonfiction tome about Star Trek tie-in literature is going to have a much, much smaller potential audience than a nonfiction tome about Star Trek TV shows and movies. Heck, that this book existed at all is kind of amazing. Has any other TV/movie franchise had a whole reference book that was exclusively about its tie-in books? Well, I wouldn't be surprised if Doctor Who did, and Star Wars has such exhaustive coverage of every bit of minutiae that they very well might as well, but it can't be that common.
As you guessed, there are a couple licensed
Star Wars publications along these lines:
The Essential Reader's Companion, a guide to all prose fiction, and two
Panel to Panel books covering the comics.
In the
Doctor Who world, Big Finish has published four such books:
The New Audio Adventures: The Inside Story (covering audio dramas, 1998-2003),
Bernice Summerfield: The Inside Story (covering all books and audios to feature Benny, 1992-2010), and two
The Big Finish Companion volumes (covering all their audio dramas from any series, 1998-2013).
I don't think there are any other licensed
Doctor Who books covered licensed fiction, at least in the style of
Voyages of Imagination. There is
The Target Book, an unauthorized history of the novelisations. Another publisher did a book about the fan audios that preceded Big Finish (
Jusytce Served: A Small Start with a Big Finish), and a second book all about a single audio drama (
The Natural History of The Natural History of Fear). Mad Norwegian has periodically announced guides of various sorts, but they always seem to end up cancelled. (I'm probably forgetting something.)
(EDIT: I was, there's an unauthorized comics guidebook by Paul Scoones. Of course, there's one of those for
Star Trek too, a not-very-good one by Alan J. Porter.)