Few more points about security, although that mailing it to yourself is very wise.

-remember to be very careful in discussions with publishers. If you discuss an idea openly before making sure it's yours (or without Confidentiality Agreement), you disclose it (so you can't patent it, if it was an invention) and it can become publicly owned, making it difficult to prove your ownership of it.
-If you in a discussion seem to agree even verbally to give your Intellectual Property Rights to the company, it is incredibly difficult to make it clear that that was not what you wanted to do.
-Copyright is always yours, but that doesn't always give full protection or isolation, it's fairly easy to go around.


There's a story about a man who had a really good idea, and he found someone who was interested in financing it. He travelled all the way across the coutry to meet this financer. But in the meeting, the financer refused to sign confidentiality agreement. He just said "What are you going to do? Go home without telling me your idea?" And the man said "Yes" and left without telling the financer the idea.

If someone gets upset about confidentiality agreement when discussing a new possible project with the author, there's always reason to think "why are they so upset about it?" Maybe the answer is "because they want to steal your idea."