If you're part of the Royal Conservatoire of Scotland staff and student community, the Whittaker Library offers a copyright page on Mahara - you'll need to login to visit this site.
There's also a great page of FAQs (Frequently Asked Questions) on the IAML(UK and Ireland) website. (It's the professional association for music libraries, so you can trust the information you find there!)
What categories of work are protected by copyright? Visit the FAQs!
What is the public domain? We have the answer to that, too!
And where do you go for the answers to all your questions?
IAML (UK and Ireland) homepage: http://uk-irl.iaml.info/index.html