Although it is completely true that any work copyrighted more than 75
years ago is now in the public domain, the reverse is not necessarily
true.  That is, it is not necessarily true -- though it usually is --
that a work copyrighted within the past 75 years is still protected by
copyright in 1997.  For that to be true, several things must also be true:

First, the original copyright claim must have been valid, in that there
must have been a copyrightable element in the work, and all copies
published must have borne a copyright statement in the form "the word
'copyright' or the copyright symbol, name of claimant, date of copyright".

(Note that this is no longer a requirement for valid present-day
copyright, though it was up until around 1980, when the U.S. signed the
Berne Copyright Convention.)

Second, -- and here is the requirement which most often goes unfilfilled
-- the copyright must have been renewed in its 28th year, if the original
copyright was claimed more than 28 years ago.

Under pre-1976 copyright law, a copyright was good for 28 years, and could
be extended for another 28 by the action of renewal on the part of the
copyright holder or his assigns; at the end of the 56th year, the work
entered the public domain.

Most tunes of interest to us today were commercial successes and copyright
WAS renewed.  But some tunes were not worth the trouble and the cost of
renewal.  Those tunes are public domain material today, although they were
created within the past 75 years.  The only way to determine whether a
copyright was renewed, as far as I know, is to consult the Copyright
Office files.

Harvey Roehl wanted to use an old tune about Lindbergh on a CD he is
issuing.  The tune was composed and copyrighted in 1927 during the
Lindbergh craze.  The compser and the tune were sufficiently obscure that
the copyright was not renewed in 1955, when its first term expired.  So
the tune effectively entered the public domain on January 1, 1956, and
Harvey is free to use it on his CD without obligation to anybody.

Matthew Caulfield

 [ I love "Lindbergh, the Eagle of the U.S.A!"   -- Robbie ]