Start with a soft reset. Hold down the power button; when the popup appears asking if you want to power off, ignore it. Just keep holding down the power button until the device turns off. Then power it up again.
Next, check your profile and make sure you have a blue "checkmark" next to Books, Magazines,Apps (and not a " - ")
When you select Library, look at the Books option. To the left of the word is an arrow/caret. It defaults to the left. Tap the arrow so it faces downward; this should display the most recent books you've opened below the word "Books." If you just tap the word Books, this should allow you to see all your books. Sometimes there used to be a lag while the entire list populates itself. The most recent update seems to have made it a bit snappier though. This works for Magazines, Apps, Catalogs, etc.
See if any of these ideas work to clear up your issue.
I tried your suggestion, so far so good. Will report back to let you know if the problem is truly resolved. THANKS!
I have a Nook HD+ and I absolutely love it. However, I am having a problem with my library and apps pages. Frequently I will tap the library screen and it will be blank or it will show the listing for example, books, Magazines, files etc. but won't show the actual files. Basically I can see "Magazines" (the word) but can't actually see my titles. Or I will click on apps and the screen will just say "apps" on the top and nothing below. I do NOT want to do a factory reset if I can help it due to all of the files I have on my nook HD+. Any ideas?
Your second description sounds like you may have the categories "collapsed". Next to each category name (Books, Apps, etc) is a circle with a triangle in it. Tapping it once will either collapse or expand the category. This allows you to minimize categories you don't use at all.
Your first description mentions sometimes the page is blank, so maybe there is something else to your issue as I am stumped on that one.