[DaleDe]

Originally Posted by Hatgirl

<docauthor> isn't exactly metadata, it's an element of an ncx file. Look here:

NCX specification as used in EPUB idpf specification document

Wiki description of ncx elements, includes <docauthor>

Anyway, I've found my answer here. It seems the answer is

  <docAuthor>
    <text>Jane Doe</text>
  </docAuthor>
  <docAuthor>
    <text>John Smith</text>
  </docAuthor>

Of course, whether the current range of reader use it is another question alltogether

ePub uses the DTbook specification but only recognizes some of the elements. It does not use the docAuthor from this file.