Comment by pmontra

unrar didn't work on Ubuntu 16.04, but rar did:

    $ unrar e shakespeare.part001.rar
    unknown archive type, only plain RAR 2.0 supported(normal and solid archives), SFX and Volumes are NOT supported!
    All OK
    $ sudo apt install rar
    $ rar x shakespeare.part001.rar
    ...         shakespeare.html                                          OK 
    All OK