Some additional info:
I've tried using the "Find Topic" tool, but it fails to see
them.
The Topic List appears to only be showing topics that were
linked to the TOC prior to the import. After importing, I'd
modified the TOC to include the new topics and had begun applying
new formatting to them, saving as I went.
For some reason, the TOC has reverted to the one prior to the
import. I don't think the import caused the crash, as I'd been
working for at least a half hour or more after the import before
the crash.
Now, the Topics List doesn't appear to show any topic that
isn't on the TOC, and I can't find any way to "refresh" or
otherwise get the Topic List to show everything.
If anyone can tell me how to get these to reappear, I'd be
grateful! My frustration and tolerance level with RH is about at
its end. The problems and issues I'm encountering are getting
ridiculous, and losing 2 hours' worth of formatting work on saved
topic files (which I can see in Windows Explorer (with the new
formatting) and which RH detects when attempting to re-import) only
for RH crash and then be unable to find them is inexcusable.