Bookmarking physically marks the page with a yellow marker, which stays on the page until it is deliberatly removed. You can search through all the bookmarks and jump to anyone to start reading there.
Last Reading Page remembers the last page so that you can resume reading on that page. You can deleberately save any page as Last Reading Page. The program also automatically saves a page as Last Reading Page when you
1. Tape the Home button.
2. Insert a Bookmark.
3. Tape 'Search Icon'.
4. Tape 'Show All Bookmarks'.
Saving the Last Reading Page automatically allows you to go back to resume reading on that page, even if you forgot to save it.