The details of copyright protection, including the length of time copyright protection lasts, varies by country. However, in the U.S., it is a total mess.
The U.S. Constitution simply says "To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries." The problem is (1) the definition of "limited Times" and (2) "Authors."
In the first issue, the courts have ruled that, although "limited Times" cannot be interpreted as "forever", copyright can be renewed. As a result, in practice, "limited Time" can become forever.
In the second issue, authors now commonly transfer their rights to publishers. So the publisher becomes the copyright owner. This is (in my opinion) completely contrary to the INTENT of the writers of the constitution. They would have never wanted business organizations to hold control over writings and inventions forever. The whole point of the constitutional clause was to allow an inventor (a person) or a writer/composer (a person) to enjoy an initial profit from their work. Once they had made their profit, it would go into the public domain and all people would then benefit from it, thus promoting *progress* of science and the arts.
The U.S. copyright laws are now so restrictive that the period of copyright extends 70 years after death of the author, or even 120 years from the time the work was created. This has no connection with the original intent of the constitution. It is idiocy.
The Broadway composer made his profit from his music. He had hit shows on Broadway, he sold his music at that time. Legally, the way the copyright laws are now interpreted, he can still profit from selling the scores. But in constitutional terms (my opinion only) he has derived his profit and that is the end of it.
Unfortunately, there is a secret trade agreement being hammered out worldwide -- ACTA. The U.S. is trying to force all other countries to conform to highly restrictive regulations drafted by the U.S. music and film uindustry associations (RIAA and MPAA). They are trying to keep these negotiations secret, because since it is a *treaty*, it would override any local laws. It is a very volatile issue, and most of the world public do not want these kinds of restrictions. As one example, in the U.S., this treaty would basically eliminate the entire concept of "fair use" of published information in education and for personal use.
ACTA here --
http://en.wikipedia.org/wiki/Anti-Counterfeiting_Trade_AgreementThere are many problems for authors and composers in the digital age. I think we all want composers, musicians, orchestras and record labels to survive. And most of us here buy a lot of CDs and a lot of downloads. It is important that composers and authors do profit from their work. But it is obvious that the old days of paper publishing are long gone, and that the industries of music and publishing will need to change in order to remain solvent in this digital era.
iTunes and Rhapsody are examples of one fact. If music is easily available at a reasonable cost from one, easy to use internet provider, customers will pay for music. The same can be said for electronic publications. However, simply ranting about "illegal file sharing" will solve nothing. Give people an opportunity to buy, don't treat your customers like criminals.
Of course, that is all just my opinion, and it is based on our situation here in the U.S. Things are likely different in other countries.
Sorry -- rant now over.