I would have thought that, since the visual companion was a companion to the film rather than the book, the right to publish would derive from the film or merchandising rights rather than the book rights. So I am not sure why the estate's permission was required in this case. Then again, I suppose it counts as a "literary work" (
) and therefore falls within the book rights. In which case the estate's permission will have been required for every publication which "tells the story" (as opposed to telling of the making of the film etc).