[ATDrake]

When you delete your books via the Manage Your Kindle page, you delete them permanently. They're gone forever from your account and if you ever want to get them back, you'll have to buy them a second time. Each and every one.

Whether or not you can continue to use your previously downloaded books after deletion depends on which device they were encoded for. If you have a copy of a book that you got via Transfer via Computer for your Kindle, you will only ever be able to open it upon that Kindle again, and you will not be able to read it upon any future Kindle you buy, or Kindle for PC/Mac/iPhone/Android, unless you strip the DRM.

Same thing works in reverse in that books downloaded via Kindle for PC/Mac/etc. cannot be transferred to any other Kindle device, unless the book happens to be one of the relatively rare DRM-free offerings on Amazon's site (or you strip it).

Whispernet downloaded books do not have an automatic tandem computer download. You can back them up by copying them from the "documents" folder on your Kindle, but again, they're coded to work only on that Kindle.

What I suggest if you don't want your daughter to see your books and aren't prepared to trash however many purchases you may have made, is to create a second, separate Amazon account and register your Kindle to that. That way, she won't ever see your regular archives.

If you download the Kindle for PC/Mac app and install it, you can still do your shopping via your original account. To transfer your books to your Kindle for reading, just temporarily re-register it to your original account just long enough to put the books you want on there, then de-register it back to the new account which won't have anything in the Archives that you might worry about your daughter seeing.

Hope this helps.