All creative works automatically enjoy copyright protection even without registration with the US Copyright Office. Therefore, you don't need to register a copyright, but there are significant benefits to registering and it's cheap. See the link below which explains these issues more in-depth. To answer your other questions, you can register a copyright for any work of authorship (that you created yourself or for some other reason own the copyright for the work).
This answer is for informational purposes only and does not create an attorney-client relationship between us.
Your friend is right legally, but leading you astray. Under 17 USC 102 copyright is automatic. However what makes a copyright VALUABLE is a prompt copyright registration, because you need a registration to sue to enforce the copyright in the USA., and you need a registration to collect "statutory" damages, which are potentially huge.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
The quick answer is "Yes it is true" that when you write a book you automatically obtain the copyright in the book. Once an expression if put down on any form of medium - paper, digiital, canvas, film - copyright attaches to the author. But how do you prove you wrote it? How do you prove when you wrote it? Registration with the Copyright Office (and the Writer's Guild) provides you with definitive proof that you were the first person to claim ownership over a particular piece of work. While its always best to have alwyer look over or fill in a copyright application, Copyright Registration can be done cheaply online so there is no reason to not register. As for works that already have been published, the application for copyright will ask you for the date of the first publication of the piece.
The answers given are informational only and do not constitute legal advice. Please feel free to contact me if you want to obtain legal advice from me.
You do get a copyright, but apply for one to enforce it.
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