Yes, you really do.
You owe it to yourself to file formal copyright — it protects your work. (Simply mailing a copy to yourself won’t offer the same levels of protection.) The cost is likely less than you would expect – the Copyright Office of the U.S. Government charges $35 for most individual filings and $55 for filings involving more than one contributor (such as a children’s book author and illustrator.) You can do that yourself, or have Braughler Books handle that for you, for an additional $20 fee.
Learn more about copyright from the U.S. Copyright Office:
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