DotReader requires Perl and a web browser, which currently is IE for Windows and Mozilla (FireFox?) for Unix. Using web browser technology for e-books makes sense, but it complicates portability. The developers imply
here that eventually dotReader will use the webcore XHTML widget .
The beta release only reads "Thout 1.0 internal format" files, i.e. for most people only the books bundled with the beta. It is supposed to eventually read many formats.