I am writing this not as an attorney but as a reasonably informed
layman.  I have addressed some of these points before in the MMD,
but here I will try to be comprehensive, focusing particularly on
United States copyright and on musical composition copyright.  In the
U.S. Federal copyright law was embodied in the Copyright Act of 1909,
until being overhauled and reformulated by the Copyright Act of 1976.

While there used to be vast differences between European copyright
principles, which were embodied in the Berne Convention signed in
1880, and those followed in the U.S. under the then-current American
copyright law, those differences were narrowed in two steps: first by
the U.S. signing the Universal Copyright Convention (1952) and then by
its enactment of the Copyright Act of 1976.  For the principles of the
the two conventions just mentioned, see the Wikipedia articles on each.

First, copyright automatically invests in the creator (author,
composer, designer) of a work.  Under the Copyright Act of 1976, the
act of creation alone endows the creator with copyright protection
-- no further action or notice is required.

This was not true under the Copyright Act of 1909.  All copies of a
work had to bear a dated copyright notice, the copyright claimant had
to file a notice with the Copyright Office (a department of the Library
of Congress) and deposit two copies of the work there.  A copyright
owner may transfer or assign his copyright to another, if he chooses.

Second, no copyright lasts forever.  Copyrights, like patents, expire.
Under the 1909 act, copyright lasted for a fixed term of 28 years, and
could, upon application by the copyright owner, be renewed for one more
28 year term.  But after 56 years, the work entered the public domain.

Under the 1976 act, the length of copyright for any work created was
originally the life of the author plus 50 years.  This change brought
U.S. copyright law closer to European law.   But then in 1998, the
Sonny Bono Copyright Term Extension Act lengthened the term to life
of the author plus 70 years.  The Bono Act also extended other term
provisions, so that the term for an anonymous or pseudonymous work or
work created  for hire is 95 years from publication or 120 years from
creation, whichever comes first.

Third, a person cannot edit a copyrighted work or arrange a copyrighted
composition and claim copyright on the edited/arranged work without the
permission of the original copyright holder.  Such modification
infringes the original copyright holder's rights and is actionable in
court.

A famous example of musical infringement was the action brought by the
holder of the copyright on the melody "Dardanella" against the composer
of "Kalua," which had similar passages.  The court held that "Kalua"
did infringe on "Dardanella," although the infringement may have been
"innocent infringement" simply from having heard the then-popular
"Dardanella" so often.  Monetary damages, but not punitive damages were
awarded to the plaintiff.

Fourth, under a U.S. Supreme Court ruling (White-Smith vs. Apollo,
1908), sound recordings were held not to be copies of a musical
composition.  So in the Copyright Act of 1909, sound recordings fell
into limbo, outside of Federal copyright law.  Although sound
recordings were subject to state laws or common law, this protection
was extremely weak.

The 1976 copyright revision and preliminary Congressional acts leading
up to the 1976 enactment finally made sound recordings copyrightable.
Various grandfathering provisions plus the Bono amendments make the
subject of sound recording copyright a minefield to explore.  It appears
that it will be the year 2067 before sound recordings made before
February 15, 1972, fall clearly into the public domain.

A further complication in the sound recording legislation is the
Compulsory Licensing provision.  That provides that a holder of a
copyright on a musical composition may forbid all recording of that
composition for profit.  But if he licenses one recording of the
composition, he must permit all others who wish to make recordings to
do so.  If the fees for such recording are not agreed on, then the fees
stated in the Compulsory Licensing law apply.

Fifth, while purchase of a copy of a copyrighted item, whether it be a
book, a picture, or a sound recording (music roll), gives the owner the
right to private enjoyment of his purchase, it does not convey to him
any right to use the item in public in any way that could be construed
as conveying to him a material benefit.  Thus, using a recording as
background music in a restaurant infringes on applicable copyrights,
whether composer copyright or performance copyright.

Copyright is an extremely complex issue.  There are a number of Copyright
Office circulars available on the Internet to answer questions.  Here is
one very useful circular: http://www.copyright.gov/title17/92chap3.html 

But ultimately copyright issues are resolved by the courts.  The
U.S. Copyright Office does not solve them, although its records and
registration applications may be used in court to show ownership and
priority of claim.

Matthew Caulfield
Irondequoit, New York