Well, I can partly explain from first hand experience! I parted company with my old agent at A M Heath a few years ago. They had sold three books to a British publisher, and foreign rights to four other publishers.
Now, all my royalties still come through them. If I have any questions about late royalties etc, I have to ask them. In a few cases, I have gone over to dealing with the subagents concerned in the relevant countries, as their responses are much quicker. So as long as these books are in print, the agency keeps earning commisions from royalties.
One of my books has gone out of print and I have asked the (British) publisher to reprint. If they do not reprint within six months I can look for another publisher, and it seems as if they are hanging on to the rights for as long as they can.
I will soon be querying again and if I get a new agent, and the first book is out of print, and I sell another novel, the first one will be mine to sell again.
