calibre
calibre is a powerful and easy to use e-book manager that includes tools to view, convert, and manage a collection of e-books. You may download calibre from the calibre web site.
When Gedcom Publisher starts, it will attempt to find calibre and add its e-book viewer as an item on the File > Browse Book submenu.
If you have installed calibre in a location that Gedcom Publisher does not search, add calibre as a Viewer tool as described on the Tools page. calibre includes several .exe files. The viewer is named ebook-viewer.exe, and that is the program you configure Gedcom Publisher to use.
The locations that Gedcom Publisher searches are listed below. If you accept the default values when you install calibre, it will be installed in one of these locations.
c:\Program Files\Calibre3\ebook-viewer.exe c:\Program Files (x86)\Calibre3\ebook-viewer.exe