I have not yet completed a manuscript, but am asked by an agent to submit a description of my book. I have not copyrighted it, as yet. I am concerned about getting ripped off.

1. How can I protect myself in this situation and still get the agent's assessment?

2. At what point should I file for copyright and how is that done? How finished must the manuscript be?

3. If I submit a related article to a periodical before the book is done, do I need a separate copyright and at what point should I submit the article relative to the book completion schedule?

Thanks in advance for any advice you can provide.