justin@utcs.UUCP (Justin Bur) (10/14/84)
The ISBN is a 10-digit number first used in Britain in 1968 and now
used in much of the world.
The ISBN has four parts: group identifer, publisher identifier,
book number, and check digit. Group identifers 0 and 1 are for
the USA, Canada, Britain, Australia, and other largely English-
speaking countries. 2 is for France, French Canada, and other
French-speaking areas. 3 is for German-speaking countries; 4 for
Japan; and so on. Some group identifers are 2 or more digits long.
The publisher identifier is assigned by the national ISBN agency
in each country to anyone publishing a book. Publishers with high
output are given short identifiers so more digits are left over for
the book number.
The book number is assigned by the publisher. Some publishers, such
as Penguin, include subject or series information in the book number;
but every publisher chooses its own numbering system (as long as it
conforms to the ISBN rules).
The check digit is calculated by multiplying the first digit by 10, the
second digit by 9, ..., and the ninth digit by 2. The check digit is
11 - ((sum of those products) mod 11). If the result is 10, X is used.
An example (the Penguin Classic edition of Homer's Odyssey):
group publisher book number ......
0 1 4 0 4 4 0 0 1
x 10 9 8 7 6 5 4 3 2
-- -- -- -- -- -- -- -- --
= 0 + 9 +32 + 0 +24 +20 + 0 + 0 + 2 = 87; 87 mod 11 = 10; check dig = 1
For more information, see the introductory pages to British Books
in Print, especially the 1969 or 1970 editions.