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.
Star Wars recently had a book out devoted to the books and novels, though I don't think it has anything behind-the-scenes [oh, I see someone's already mentioned it]. Doctor Who had a set of 3 large, unauthorized, unofficial guidebooks that extensively cover the many novels that were being released between the old series and the new series (Stevil2001, I agree it's been baffling and disappointing seeing Mad Norwegian Press stall on some of the projects the announce; their I, Who volumes 1-3 are great). The coverage is exhaustive, but they also don't really have a lot of behind-the-scenes information. One fan even did a guidebook for the DW annuals that were always coming out during christmas while the old series was running, and that book does have a couple of short chapters about the making of them; and that one is a whole different level of obsure.
Talking generally, I quite like Voyages of Imagination, and found it useful and interesting. But it wouldn't have helped me conceptualize the idea of the 1980's era ST novels as innovating their own continuity before the coming of TNG. OTOH, while I may have been inspired to buy a handful of Trek novels that I hadn't bothered with before, the threads about 80's Trek lit caused me to track down and buy and insane amount of those older Trek books. I like VOI, and am glad it exists, but I think there's been some fair critique of it brought up in this thread. I too was surprised by the space allocated to covering some of those anthologies that don't seem very mainstream. It is a little galling to see The Final Reflection neglected, it had an impact, it inspired future TV Trek writers, it has connections to an RPG suppliment, the Klingons culture is developed differently that can be detailed in brief, ect.
I'm not going to get too picky. I have and like VOI. I have information I compiled from this forum as a guide to the 80's Trek continuity. I have some printouts for what I'll call the Klinzhai version of the Klingon language (for lack of a better label) and it's canon (I really hate that word) counterpart, the Klingon/English dictionary. And...I have the books themselves, the ones that I've read, and look forward to reading in the near future.