Quote Originally Posted by cool pop View Post
Course you're allowed to do whatever you want with a book you self-published because you own all the rights and have no one to answer to legally but yourself. So going from self-publishing to trade publishing is no issue (if you can get into trade publishing, it's up to luck, fate and a whole lot of other things out of a writer's control).

Now going from trade to self-published can be difficult because when you are contracted to a publisher, they hold the rights. Some publishers allow authors to self-publish while publishing books with them but many don't. Some have clauses where you cannot self-publish or write for other publishers while having a contract with them.!
They only hold the specific rights you assign to them. Don't sign a contract that grabs all rights and/or that doesn't have a specific time limit.

Rights include things like derivative works, subsequent non-related works, film rights, international rights, audio rights, ebook rights, translations . . . this is one of the areas where having a good professional, knowledgeable agent negotiating for you is an asset.