Okular is a universal document viewer developed by KDE. Okular works on multiple platforms,
including but not limited to Linux, Windows, Mac OS X, *BSD, etc.

Features:
<ul><li>Supported Formats: PDF, PS, Tiff, DjVu, Images, DVI, XPS, Fiction Book, Comic Book, Plucker,
EPub, Fax</li><li>Sidebar with contents, thumbnails, reviews and bookmarks</li><li>Annotations support</li></ul>