I can break this down in a way that’s easy to grasp. The copyright for an 'all rights reserved' book typically belongs to the author who created it, unless they’ve signed a contract transferring those rights to someone else, like a publisher or a production company. This is standard in traditional publishing deals, where authors grant publishers exclusive rights to distribute their work, but the copyright often remains under the author’s name unless it’s a work-for-hire situation. For example, if you write a novel and publish it yourself, you hold all the rights. But if you sign with a publisher, they might control distribution rights while you retain ownership of the characters and world.
There are nuances, though. In collaborative works, like anthologies or shared universes, copyright might be split between contributors or held by the entity that commissioned the work. Fan fiction exists in a gray area—original characters belong to the writer, but the universe might be copyrighted by the original creator. It’s why platforms like Archive of Our Own emphasize transformative works. And let’s not forget estates—copyright can extend 70 years after an author’s death, managed by their heirs or a literary trust, like how the Tolkien Estate oversees 'The Lord of the Rings.' Always check the fine print, because copyright isn’t just about who wrote it; it’s about who controls how it’s used.