ISBN definition

[GSCole]

A few years ago, I innocently asked a reference librarian how the ISBN
check digit was calculated.  My subsequent search took me through the
reference desks of several large libraries, including the Library of
Congress.  While none had the answer, at that time, the Library of
Congress pointed me in the direction of R. R. Bowker, which sent a very
informative booklet.  Their similarly informative web site is:
http://www.bowker.com/standards/

The ISBN seems to be something that many of us take for granted, but it
can be quite informative when looking at what appear to be two copies of
the exact same book, same publisher, edition, and so on.  Different
ISBNs = different books.  [Unless there is some exception to the process
that has eluded me thus far.]

George S. Cole  gscole at ark.ship.edu
Shippensburg University