I think I found a data-entry typo. (Is there a better place for me to report these?)
The three headings starting at the link below all have exactly the same "The E-book Viewer" content:
http://calibre-ebook.com/user_manual...-e-book-viewer
==The calibre e-book viewer==
* The E-book Viewer
* Starting the viewer
* Navigating around an e-book
* Customizing the look and feel of your reading experience
* Dictionary lookup
* Copying text and images
==Customizing calibre‘s e-book conversion==
* The E-book Viewer
* Starting the viewer
* Navigating around an e-book
* Customizing the look and feel of your reading experience
* Dictionary lookup
* Copying text and images
==Editing e-book metadata==
* The E-book Viewer
* Starting the viewer
* Navigating around an e-book
* Customizing the look and feel of your reading experience
* Dictionary lookup
* Copying text and images