Copyright is an important topic for every musician that is serious about his work. It is also a dangerous topic to comment on. Firstly, it is a confusing web of legal issues that keeps many lawyers employed - and I am not a lawyer. And secondly, copyright law varies from country to country - though many countries have now standardized. So don't take this article as legal advice. Hopefully it will offer sensible advice to musicians in most countries. I advise you to do some research of your own, and consider paying someone qualified for some real legal advice.