I am not sure how or why, but using the backspace key to edit the title of a new bookmark I was creating ended up wiping out every bookmarks folder above the letter N (was adding a bookmark to the "News" folder). Is there is a quick way to recover all of these? It was a large number bookmarks. :-\
That hardly seems possible. Did you restart to see if they are really gone?
In your user folder there should be an automatic backup created. It should be named Bookmarks.bak. But if you have already modified your Bookmarks again you have probably lost it.