Congratulations for having a contract that said all rights revert to you if the book falls out of print.
I believe I read a few months ago that some major but obviously scumbag publisher actually tried to establish contracts that said they retained rights to the books even after they were out of print. This elicited enormous howls of outrage (and lots of bad publicity) and they hastily backed off. Traditionally,
all books that fell out of print had their rights revert to the author. With or without a contract, I believe.
But let's say that I'm a S.F. author who hopes to sell a novel per year to Tor. (Which was indeed my case.) By the time my 4th book has been published, my first book is almost certainly "out of print" and, as I think the contract says, two years have gone by since it went out of print.
Upon written request by me, I get the rights to that book back.
But by doing so, I would probably be thumbing Tor's sense of self-esteem right in the eye. They would give me back the rights -- but, unless I was a Steven King-type author, they would almost certainly not bother to buy my 5th book.
So the situation could be more complicated than you might think. Having known a fair number of writers over the years, I would say that almost *none* of them would try to get the rights back to the earlier books
unless those are
paperback, reprint rights. Then it would be a very common case. Jack Vance, say, might have written 40 hardback novels for Tor, which still retained all the hardback rights, but might have 6 different paperback companies releasing his reprints. And he would keep regaining rights to those reprints as soon as possible after the reprint editions fell out of print. People like Heinlein, say, and Vance, have had
many different publishers for their reprints. (And, I guess, the
original hardback publishers are still sharing in the sales to the reprint houses.
