The command line interface documentation is not out of date. It is auto generated from the actual code, at every calibre release.
And if you want to generate a list of authors, you need to be able script, for which windows is rather painful. On linux or OS X, it is simple, but on windows, without powerful command line utils, you would need to resort to using calibre-debug, like this:
Code:
calibre-debug -c "from calibre.library import db; db = db().new_api; print '\n'.join(sorted(db.all_field_names('authors')))"
And on window you would need to redirect the output of that command to a file, as the windows console cannot handle large amounts of output.