One of the questions that comes up over and over again among new writers is "How do I protect my work?" We're all excited about the writing we've done, we want to get it out there to readers, but we want to be careful about protecting the work.
The most frequent question in this realm is, "How do I copyright this work?"
The US copyright office defines copyright this way:
Copyright is a form of protection provided by the laws of the United States (title 17, U. S. Code) to the authors of “original works of authorship,” including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. Section 106 of the 1976 Copyright Act generally gives the owner of copyright the exclusive right to do and to authorize others to do the following:
• reproduce the work in copies or phonorecords
• prepare derivative works based upon the work
• distribute copies or phonorecords of the work to the public by sale or other transfer of ownership, or by rental, lease, or lending
• perform the work publicly, in the case of literary, musical, dramatic, and choreographic works, pantomimes, and motion pictures and other audiovisual works
• display the work publicly, in the case of literary, musical, dramatic, and choreographic works, pantomimes, and pictorial, graphic, or sculptural works, including the individual images of a motion picture or other audiovisual work
• perform the work publicly (in the case of sound recordings*) by means of a digital audio transmission
The thing to note about copyright is that it protects the fixed creative expression of your idea(s), not the ideas themselves. That means that you can write a book about a dystopian future in which the bad guys breath carbon dioxide and someone else can do the same thing. That's not infringement. It becomes infringement when they begin to copy your actual expression of the idea.
Copyright is automatically in effect from the time that you create the work in its fixed expression. So, your work is automatically protected. But... there are some good reasons to register the copyright with the US Copyright Office if you have concerns about infringement. Most importantly, timely registration (within 3 months of publication or before any infringement occurs) entitles you to statutory damages in the event infringement occurs. If you haven't registered before infringement occurs, you're eligible only for actual losses / damages. In publishing, that can be somewhat harder to prove (unless you have a runaway hit on your hands).
So, if you're concerned, go ahead and register your work with the US Copyright office (http://www.copyright.gov). It's $35 and some paperwork. We'll link to some resources below, but remember that we're not lawyers -- if you have questions, you should consider talking with an intellectual property lawyer to get thorough, accurate answers.
Oh, and a quick note about "the poor man's copyright" ... you'll find all kinds of crazy ideas on the internet. One of them is that you somehow prove something in court by mailing yourself a sealed copy of your manuscript. Nope! The reality is that there's no benefit to you from mailing yourself a sealed copy of your work. Register it with the Copyright office if you're concerned.