@sulasu: Don't do it. Unfortunately, the way that calibre writes the authors to the book when you send it to the device is not the way the Kobo wants them. It only reads the first author. And it want multiple authors in the format "FN1 LN1, FN2 LN2". You can get calibre to set the author in the way Kobo likes it with a metadata plugboard. Set the author to:
Code:
program: raw_list('authors', ', ')
With that, calibre will match most multi-author books.