This book is basic reading for music majors and professional musicians. It has more than once been highly recommended to me by serious professionals and instructors and coaches in college-level courses and summer music programs.
Even if much of the material in this book involves considerable detail on legal questions, which makes it a difficult read, the sheer amount of information it contains and conveys is great and provides answers to many questions that musicians will have. It is therefore also a great reference source.
At first glance, the book seems geared mainly toward those working with popular music. Nevertheless, its content actually applies to classical musicians as well. It is worthwhile, interesting, and highly recommended reading, especially if you are just getting into the business side of music and have real concerns about copyright, public domain, negotiating contracts, agents, and so on.