I was thinking about rights today, did a little googling, and found this article written last year.
It emphasizes why it’s a good idea to keep an eye on the reversion clause of your contract. I have 13 books that have reverted back to me, but it didn’t happen without diligence. Some contracts stated that rights would revert seven years after the book was out of print. For others, it was only three or four years. So I had to keep track of the approximate date the books went out of print. Which happened to be almost immediately for most of them. :D Once the time period was up, letters requesting the reversion of rights were sent to the various publishers. For some, this process took months and required several signatures. Others went fairly quickly. I think one publisher signed off early.
I have no plans for the books. I haven’t made any attempt to sell them to another publisher. But I like the idea that they are once again mine and in my control. I prefer to have them languish and grow old at my house rather than at a publishing house.