ISBN, SBN, LCCN and the other numbers in a book

Turn over a paperback from the 1980s and you may find two barcodes, a price code, an ISBN and a row of digits running down to 1. Each one tells you something different, and together they are usually what separates one printing from the next. On a ctlgs edition they all go under Identifying Codes, one row each, with a type picked from the list and the code copied exactly as printed, hyphens and spaces included.

Where to look

Most codes sit on the copyright page, the back of the title page. Barcodes and prices are on the back cover or the dust jacket. American mass-market paperbacks often carry a second barcode inside the front cover. Publishers' own catalogue numbers turn up on the spine or the front cover, like the Bantam number printed beside the price on old Bantam paperbacks. Library data sits in a block on the copyright page, usually headed "Cataloging in Publication".

SBN, ISBN-10 and ISBN-13

SBN. Britain's Standard Book Numbering scheme began in the late 1960s and gave nine-digit numbers. It turned into the ISBN in the early 1970s: put a 0 in front of an SBN and you have a valid ten-digit ISBN with the same check digit. If the book prints "SBN", choose "SBN" and copy the nine digits.

ISBN-10. The International Standard Book Number became an international standard in 1970. It has ten characters in four groups: a country or language group, the publisher, the title, and a check digit, which can be an X. Choose "ISBN 10".

ISBN-13. Thirteen digits, starting 978 or 979. The 2005 revision of the standard defined it, and from 1 January 2007 every new ISBN had to be thirteen digits. Between those dates many publishers printed both forms, so a 2005 or 2006 book can carry an ISBN-13 too. Choose "ISBN 13". An older book reissued after 2007 gets a thirteen-digit ISBN even when the text is decades old.

The list also has a plain "ISBN", which many older entries use. Count the digits and pick the specific type when you add one. A book often prints more than one ISBN, for the hardback and the paperback, or for the set and the volume. Add each one, and say in Notes which is which if the book does.

The barcode and the add-on beside it

The barcode on a book is an EAN-13 whose number is the ISBN-13: 978 or 979, then the first nine digits of the ISBN-10, then a new check digit. On a book printed before 2007 the barcode still reads 978…, even though only the ISBN-10 is printed above it. The hardback of How to Be a Villain has ISBN 0-8118-4666-0 on its copyright page and 9780811846660 under its bars. Choose "Barcode (EAN)" for a 13-digit barcode and "Barcode (UPC)" for a 12-digit one. Keep plain "Barcode" for a code that fits neither standard, or one printed with a mistake.

To the right of the main barcode there is often a smaller one with five digits. This is an add-on. It is not a code on its own: it belongs to the barcode beside it. On American books the first digit 5 means US dollars and the other four are the price, so 51295 is $12.95. Canadian prices start with 6. A plain 90000 means the publisher printed no price in the add-on. The first printing of How to Be a Villain has 90000; a later printing has 51295, and that change is one of the things that tells them apart. Enter the add-on as "EAN 5" (or "UPC 5" beside a UPC) in the row straight after its barcode, so the two stay together on the page. Magazines sometimes use a two-digit add-on, usually the issue number: that is "EAN 2". "EAN 8" is a short barcode for small items.

American mass-market paperbacks are the tricky case. The back cover can carry a 12-digit UPC with its own add-on, aimed at newsstands and supermarkets, while the inside front cover has the book-trade EAN with a different add-on. The Tor paperback of A Connecticut Yankee in King Arthur's Court shows both. Record both barcodes, each followed by its own add-on.

A small S in a triangle near the barcode marks a strippable paperback: unsold copies could be returned by tearing off the cover rather than sending back the whole book. It is not a code. Mention it in Notes if you like.

Magazines and sheet music

ISSN is an eight-digit number in two groups of four, such as 1234-5679; the last character can be an X. It identifies a magazine or a numbered series, not a single issue, so it stays the same from issue to issue. Put the issue in "Volume Number" and "Issue Number". American periodicals may print a "USPS" number instead of, or as well as, an ISSN.

ISMN is the music equivalent of the ISBN, for printed music. Before 2008 it was an M followed by nine digits (M-2306-7118-7). Since 2008 it has thirteen digits starting 979-0.

Library data on the copyright page

The Cataloging in Publication block holds several numbers. Enter only what is printed.

• The Library of Congress number, often printed as "Library of Congress Catalog Card Number 62-12345". Older ones are a two-digit year and a serial number; since 2001 the year has four digits. Choose "Library of Congress Catalog Card Number".
• The Library of Congress classification, letters and numbers such as PR6005.L36 A618 1997. Choose "Library of Congress Classification Number".
• The Dewey number, such as 823'.914, often followed by the Dewey edition it comes from. Choose "Dewey Decimal Classification Number".

Avoid "Library of Congress Call Number". A call number is the shelf mark one library gives its own copy. It is not printed in the book, and the classification number is what the copyright page shows.

Codes from particular countries

• DL (Spanish): the Depósito Legal, the legal deposit number on Spanish books, such as M-19673-2008 (a province code, a number and a year). "DL (Portuguese)" is the Portuguese equivalent.
• NIPO: the number on Spanish government publications.
• Wettelijk Depotnummer (WD): the Belgian legal deposit number.
• NUR, NUGI and UGI: Dutch subject codes. UGI was used until 1986, NUGI from 1986 to 2002, and NUR since.
• YKL (Finnish): the Finnish public library classification.
• BIC (UK): a British book-trade subject code.

Anything without its own type, such as a Canadian cataloguing number, goes under "Other", with a line in Notes saying what it is.

Printing numbers, prices and the rest

The number line on the copyright page goes in as "Printer's Key", exactly as printed. A printing stated in words, like "Eighth Impression", goes in as "Impression/Printing No.". The printed price goes in as "Price", with its currency. Printings, states and issue points explains why these are worth the trouble. "Catalog Number" and "Product Code" take a publisher's own stock numbers, and "Series Number" takes the number of the book within a publisher's series.

If a book prints none of these, leave the field empty rather than borrowing a code from another edition. A missing ISBN is a fact about the book too.