That is true, if and only if what they prepared is considered a derivative work, which means it has sufficient originally to acquire a separate copyright. When

That is true, if and only if what they prepared is considered a derivative work, which means it has sufficient originally to acquire a separate copyright. When the relevant copyright act was written, the assumption was that this would be things like translations, screenplays and motion pictures created thereof, or similar major derivatives that are clearly distinct from the original. Since then, jurisprudence has largely moved towards considering even smaller changes derivative works, but I'm not entirely sure if a book as laid out by a publisher with added illustrations is actually considered a "derivative work" of the original copyright in the manuscript. It is obviously derivative, as it is derived from the manuscript, but does it reach the level of a distinct "work"?