Sorry, there's no preference for sorting in that manner. Sort by Name doesn't account for the most visited, it's a straight alpha sort per folder. The Most Visited folder, on the Bookmarks Toolbar, is actually a separate algorithmic calculation based upon how often a bookmarked website is visited, and I believe that calculation includes all pages visited at that domain based upon the browsing history.

Guess I didn't ask the right question. How do I sort by name? Also, how do I learn about such things other than asking on line? In other words, "Where is the 'book' ?"

F1 takes you to Firefox Help http://support.mozilla.com/en-US/kb/Firefox+Help?style_mode=inproduct

Here's the KnowledgeBase article for that. https://support.mozilla.com/en-US/kb/Sorting+bookmarks

Bookmarks are sorted between separators. So if you have them in one big list then put your favorite bookmarks at the top and the other below separated by a separator and sort them alphabetically. You can only sort folders in Firefox 3 versions. See http://kb.mozillazine.org/Sorting_and_rearranging_bookmarks_-_Firefox

SortPlaces: https://addons.mozilla.org/firefox/addon/9275