So, after I pulled the books off the shelf, I pulled it out (fortunately it just had clearance over my monitor), flipped it over (going from "smiley shelf" to "frowny shelf"), re-set the rails, and pushed it back in. Unfortunately, it had also developed some "warp", and after I'd put in a corner brace on one side, the other was twisting away from the support. I figured that once the books were back on that, however, it would start to work its way up, so I only put in the "outer" screw on the brace arm going into the shelf, which should allow it to "pivot" on that point, and I can put in the other screw once the shelf starts getting straighter.
I still haven't started logging in those yet ... somehow having to do construction projects is messing with my idea of how long this all should take! I suspect that the shelf below it would also benefit from being flipped and braced, but I'd have to move my whole computer set up to do that. I have enough room to get the books out and logged, but there's not much I can do about the shelves (unless, of course, they fall apart while I'm working on the books, in which case I'll have to do major furniture moving).
The Wife and I have been having an on-going tiff about the bookcases in here ... first of all, she would prefer that we get rid of my office (what do we do with ME then???), and make it a "family room" for The Girls ... which is probably why she's dead-set against my doing anything built-in (which would be my preference). She's also been resistant to my getting new bookcases, even though these range from 15 to 25 years old (which is sort of pushing it for particle board!), and I could replace the lot of them for only around $400.00 (K-Mart has an almost identical unit for $39.99 each, and I could have 10 of them shipped to our local store for free, and just get a U-Haul van for a couple of hours to go get them home).
Obviously, this is one of those "hidden" issues in our marriage ... she's not a "book person", while she buys and reads a lot of stuff, it pretty much goes out when she's done with it. I "come from a place" where one's library defines who one is ... sort of like a chest full of medals on a career military guy, or some sort of totem display in a native culture. I guess this is one of the reasons that I find LibraryThing so exciting ... it's a "totem display" of my intellectual history! Anyway ... if it were up to The Wife, at best she'd have me box up all the books and dump them in storage somewhere ... such a bizarre concept!