A copyright is a way of protecting your own intellectual creative property. With the widespread use of the internet and plagiarism, it’s the best way to protect yourself. However, that doesn’t mean that you will be able to sue (think foreign country) or that you will be able to locate the person producing your work as their own. And it also costs money to hire lawyers. But since it’s so easy to do, it is still the best way of acquiring protection.
It used to be that people believed that you could acquire sufficient evidence that you had produced the work in question by mailing a copy of your manuscript to yourself and then not opening it when it arrived. This would show a postmark to prove when you wrote it. That is not considered sufficient proof and you still need to file a copyright.
You cannot copyright a title, only a longer work. Copyrights after 1978 also extend the rights 70 years after a person’s death so make sure you have a will to let your heirs know who is entitled to it.
Filing a copyright is easy. The following link takes you to the U.S. government site where you can register your work and upload it so it is on file. There are different fees, depending on the work, art, etc. but the base fee for a book is $65. There is also a link below with more details about the cost. A certificate will be mailed to you showing the registration and you can always log back in to see the status of the process.