Sumatra PDF works as a reader of multiple file formats. Obviously, it has the ability to open PDF files. But that is not all. On the app’s list of compatible formats we can also fine eBooks, XPS, CHM and DjVu. The outer look is rather simplistic but ‘ let’s be honest ‘ all you need is a space to read, even if one may consider the lack of annotating devices a downfall. At your disposal there are a bunch of keyboard shortcuts, some command line arguments for more advanced users and a browser plug-in that may turn useful when an eBook needs previewing.