A resource for public domain and royalty free music. The "Copyright Law" tab provides very straightforward, music-specific information about the subject in plain English. There are multiple screens of information; be sure to use the light blue arrows at the bottom of each screen to navigate through them.
Authored by two librarians at the Peabody Conservatory, this free online book aims to help early career musicians understand how copyright and publishing practice impact what they can access and how they create and share new work.