EPUB Viewer, by Enolsoft, is a handy program that lets you easily launch and read EPUB documents and convert those files to the PDF format. The reading features include drag-and-drop functionality, zooming in and zooming out, etc. You can bookmark a current page or print EPUB files. The tool also supports embedded audio, video and other media files. Thanks to the multiple tabs, you can work with multiple EPUB files at a time, without opening multiple windows. Not to mention, the user interface is easy to use right off the bat.